EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: pascal_sweden on May 09, 2015, 10:22:28 pm
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Very cheap 24MHz 2-Channel function generator with support for arbitrary waveforms.
They sell it on Ebay for only 130 USD, which is much cheaper than the Siglent SDG1025 :)
http://www.benl.ebay.be/itm/24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-FY3224S-/281537687541?pt=LH_DefaultDomain_3&hash=item418cf42ff5 (http://www.benl.ebay.be/itm/24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-FY3224S-/281537687541?pt=LH_DefaultDomain_3&hash=item418cf42ff5)
I understand that the Siglent provides much more features and has a colour screen, but if the FY3224s delivers the basic functionality it is required to do so, and if it is both accurate and reliable, then it could be a valid budget alternative.
Does anybody on this forum have experience with the FeelTech FY3224s function generator?
What is your experience? How accurate and reliable is it?
Is the table correct in the specifications? Does it really only support 24 MHz on the sine wave?
Is it easy to download an arbitrary waveform to the memory of the function generator?
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A similar instrument. Probably OK for hobby use. https://www.insidegadgets.com/2015/02/20/inside-the-feeltech-12mhz-dds-function-generator/ (https://www.insidegadgets.com/2015/02/20/inside-the-feeltech-12mhz-dds-function-generator/)
But that Siglent is much better.
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The case is almost empty. All the electronics are on the front panel.
Some people want to make a backplate for the front panel to make it smaller :)
Would like to know more about the internal architecture and the arbitrary waveform support.
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I purchased the FY3224s and should arrive early next week. I don't believe this box will be as empty as that other version that was linked to. That other version doesn't have nearly the features that the FY3224s has anyway. I chatted with the Chinese fellow that I am purchasing it from and he is very jazzed about the product. I will be opening it up for sure when it arrives. If it's everything it's represented to be, it's a bargain price for those features! I paid $136 for it. I also purchased the portable GK101 10MHz model with 3" touchscreen. I like it and have used it for about a week.
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Besides pictures of a tear down, can you also verify the max frequency on all the waveforms, and the quality of the produced signals?
Note that I was under the impression that it only can reach 24 MHz for sine wave, and that all the other waveforms can only go up to 6 MHz, unless the table contains a typo.
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Sure, I will post some pictures of the tear down and verify the accuracy of it's specifications. I think it's funny that you mention that it will only do 6MHz beyond a sine wave...that's better than the Siglent except on the square which is 10MHz, and it isn't the best looking square at that! 6MHz for an arbitrary waveform is actually very good. I can't see how the Siglent has much better specs at all really.
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Yes I just notice that Siglent has limitations too. Was expecting 25 MHz on all types of signals.
Must have missed that. The pulse and arbitrary go only to 5 MHz, the ramp only to 300 KHz, only the sine and square wave seem to go to 25 Mhz.
Do you know what chip they use in the FeelTech FY3224S signal generator?
Did you buy it on Ebay? There is also one on AliExpress that actually has FeelTech on the front:
http://www.aliexpress.com/store/product/24MHz-Arbitrary-Waveform-Signal-Generator-Fully-Numerical-Control-Dual-channel-DDS-Function/1770038_32326724304.html (http://www.aliexpress.com/store/product/24MHz-Arbitrary-Waveform-Signal-Generator-Fully-Numerical-Control-Dual-channel-DDS-Function/1770038_32326724304.html)
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I purchased it from eBay:
http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121478483178?pt=LH_DefaultDomain_0&hash=item1c48ae8cea (http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121478483178?pt=LH_DefaultDomain_0&hash=item1c48ae8cea)
The ones that actually say FeelTech on the front panel are the inferior ones to the FY32XX models. I have purchased much tech from the seller that I linked over a five year period. I'm in the US and his stuff arrives in about 11 days total. I'm not sure what chip it has in it, but I will know by Wednesday.
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Interesting to learn that FeelTech itself is not that good :) How did you learn about this yourself?
Looking forward to your measurements!
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Tombdiver, curious about the FY32xxS series of products. So, did you receive it yet and what do you think?
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Yes, I received the unit, unboxed it and fired it up. I was surprised to see the FeelTech name on the front panel Basically it is very similar in appearance and functionality to its predecessor the FY22XX series. I did remove the top and took a peek, but the inside is also very similar to the FY22xx series of these function generators too (EMPTY), okay, the power supply board actually took up some space on this version. It's using the Altere Cyclone chip (version 1). I was called out for work and have been busy since. I plan to get back to it soon and will post some findings and pics. Here is one picture though. Don't laugh at my BK oscilloscope!
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I think it's funny that you mention that it will only do 6MHz beyond a sine wave...that's better than the Siglent except on the square which is 10MHz, and it isn't the best looking square at that! 6MHz for an arbitrary waveform is actually very good. I can't see how the Siglent has much better specs at all really.
Risetime?
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tombdiver,
Thanks for the tease on seeing this unit. In addition to performance testing I would love to see of picture of the insides and know something about the power supply. I have thoughts of adding circuitry inside the empty space and if the supply has extra power that would be great.
Is it just the Altera Cyclone FPGA or is there a microprocessor in sight some where? If no micro then they must be using a soft core processor inside the FPGA.
gby
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Yes, I received the unit, unboxed it and fired it up. I was surprised to see the FeelTech name on the front panel
Didn't you write in the initial comments that FeelTech is inferior quality to the unbranded version?
Or was that a misunderstanding?
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I was referring to another model that had the FeelTech name stamped on it. It was inferior to this one (because it was a completely different model). I know of two others that ordered the FY3200s and they do not have the FeelTech name on them anywhere. I wasn't really impressed by this offering at first because of its lack of intuitiveness, but after about 10 minutes I felt comfortable going through the motions of its features. Is it worth $136? Yes, I think so. I have been super busy with upgrades on our network, hopefully I will get to some measurements soon.
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how does this compare to the mhs-2300a?
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There is another thread about the mhs-2300a:
https://www.eevblog.com/forum/testgear/any-reviews-or-experience-with-this-function-generator/ (https://www.eevblog.com/forum/testgear/any-reviews-or-experience-with-this-function-generator/)
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Comparison Feeltech FY3200S and MH Instek MHS-5200A
I was looking for an inexpensive small bench two channel signal generator. I wanted to be able to output sine, cosine waveforms for I and Q and then with a knob to vary the frequency from pretty low up to > 4 MHz. There are many instruments in the $250+ category that can do this but I was looking sub $100 budget. I narrowed it down to two choices:
Feeltech FY3200S:
ebay sellers: fly-xy (http://www.ebay.com/itm/6Mhz-Dual-channel-DDS-Function-Arbitrary-Waveform-Signal-Generator-Sine-Square-/111505339280?tfrom=121478479995&tpos=top&ttype=coupon&talgo=undefined), elecdesign2015 (http://www.ebay.com/itm/24Mhz-Dual-channel-DDS-Function-Arbitrary-Waveform-Signal-Generator-Sine-Square-/181775301443?pt=LH_DefaultDomain_0&hash=item2a52a6fb43)
web site: www.feeltech.net (http://www.feeltech.net/) Chinese translated to English (http://translate.google.com/translate?prev=/language_tools&u=http://www.feeltech.net/&sandbox=0&usg=ALkJrhjepBAQ7kFd84MF6xvKuw3ehWAx_g)
MH Instek MHS-5200A:
ebay seller: t-happy (http://www.ebay.com/itm/6-25MHZ-DDS-Dual-Channel-waveform-signal-generator-frequency-meter-signal-source-/181755288378?pt=LH_DefaultDomain_0&var=&hash=item2a51759b3a)
web site: www.mhinstek.com (http://www.mhinstek.com/) product not listed but can download Chinese manual, SW (http://translate.google.com/translate?hl=en&sl=zh-CN&u=http://www.mhinstek.com/&prev=search)
Below is a comparison chart between the two for the major specs and the specs I was interested in. I couldn't find a way to insert a table formatted in a word processor so it is a crude fixed width font and spaces to format for this post. |O
Specification FY3200S MHS-5200A
Sample Frequency 250 Msamp/sec 200 MSamp/sec
Waveform Resolution 12 bits 8 bits
Waveform length 2048 1024
Waveform memories 4 16
Amplitude 50 Ohm load 5 mVp-p – 10 Vp-p 7.5 mVp-p – 7.5Vp-p
Sine max frequency 6-24 MHz per model 6-25 MHz per model
Square, Triangle, Arb max f 6 MHz 6 MHz
Square rise time < 100 nSec spec ?? < 20 nSec
< 20 nSec measured
Outputs Ch 1, Ch2, TTL A, B Ch1, Ch2, TTL A, B
4 GP TTL out, 1 GP TTL In
Frequency Counter Input 2-20 Vpp, 1 Hz – 100 MHZ 0.5-20 Vpp, 0.1 Hz – 60 MHz
Freq, count Freq, count, width, duty
Power Input Ac line 85 – 260 Vac 5Vdc from external adapter
Front Panel Interface 10 Button mostly 6 Buttons must use
dedicated functions shift button for functions
Computer Control USB 1.0 USB 1.0
Dimensions WxDxH 200x190x90 mm 190x180x71 mm
Relative Ebay cost deliv US $86 6 MHz $68 6 MHz
$100 24 MHz $81 25 MHz
Based on the above comparison it comes down to need/personal preference which one is a better fit. For me I prefer the direct ac line cord rather than the wall 5V external supply and I really thought the 12 bit with 2048 waveform length versus 8 bit and 1024 had value. So, I went with the FY3206S even though it was $20 more. I will admit the MHS-5200A 4 channel general purpose logic signal pattern generator sounded interesting. But, I suspect that with only 1024 time states that their value in real circumstances is limited.
So, I bought the FY3206S and will post test data soon.
Edited 7/25/15
At this point the FY3212S 12 MHz generator is only $67.94 and thus the FY3200S's are the same cost level as the MHS-5200's.
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I have received my FY3206S generator and have had some time to test it so I thought I would share some oscilloscope screen shots and some data.
First thing I noticed is that this generator uses very little power. I powered it through Kilowatt power meter.
10 kHz Sines 10 Vp-p no load: 1 W
10 kHz Sines 10 Vp-p 50 Ohm load: 2 W
6 MHz Sines 20 Vp-p no load: 3 W
6 MHz Sines 20 Vp-p 50 Ohm loads: 3 W*
USB connection does not change power.
Nice low power :-+
I then checked out the performance with a Tektronix MDO3104 1 GHz BW, 5 GS/s oscilloscope. I connected with BNC to BNC cables with the scope set to terminate in 50 Ohm.
Per request earlier in the thread first up is rise time for a square wave. The square is nice and clean with rounded edges, linear slope, and essentially no overshoot. Measured 10-90% rise time is 19 nsec. Perfectly fine for a 6 MHz square. Feeltech spec is "<100 nSec" but 100 nSec makes no sense for a 6 MHz square so I am assuming that spec is a typo in the manual. See attached scope shot "FY3206S MDO3104 Sqr Rise 5Vpp.png". :-+
Second, we have investigation of square wave edge jitter. With the set frequency a simple integer sub multiple of the 250 MHz sample rate I could not see any jitter. I assume if I really looked I would at least see sub nSec jitter. If I picked a non-integer sub-multiple I could see two distinct edges (via scope persistence turned on) 5 nSec apart. For non-integer sub-ratios you would expect one cycle of the 250 MHz clock =4 nSec spaced edges once in a while to get the average frequency to the set point on average. I also looked 9 cycles beyond the scope trigger point to give it more chance of edge jitter. See attached scope shot "FY3206S MDO3104 Sqr Jitter 5Vpp.png". :-+
I then looked at triangle wave linearity and sharpness of the corners at the peaks. At 1 Vp-p set point yielding 500 mVpp at the scope at 1 MHz the slopes are very linear and the corners look pretty sharp. See attached scope shot "FY3206S MDO3104 1MHz Trgl 500mVpp.png". :-+
Next up is 500 mVpp triangle at the full 6 MHz. There is some rounding of the peaks and the p-p measured amplitude drops 15.6% but overall pretty nice triangle waveform for top frequency. See attached scope shot "FY3206S MDO3104 6MHz Trgl 500mVpp.png". :)
Now moving on to sine wave purity/distortion. Attached is an FFT spectrum of a 10 Vpp set point amplitude at 100 kHz. Measured fundamental amplitude is +4.8 dB or 1.75 Vrms or 4.94 Vpp (low by 1.2%). The largest harmonic was the fifth at -51 dB relative to the fundamental. Based on this spectrum I would say THD is < 0.5% although I don't have a direct THD measurement. Easily below the published spec of 0.8% at 1 kHz. See attached scope shot "FY3206S MDO3104 100kHz Sine Spectrum 5Vpp.png". :)
Lastly, I checked the noise and distortion while outputting the smallest amplitude set point of 10 mVpp. The noise on the waveform with the scope set to 1 mV/div was a fuzzy width of the sine waveform of about 0.4 mVp-p or about 0.15 mVrms which is close to the scope's measurement noise. Looking at the spectrum the largest harmonic is about 40 dB down. Note that at this small level there are harmonic lines showing up at 140 kHz which is not related to the 100 kHz sine and is either a generator noise and/a very high frequency signal aliasing on the scope's 100 MS/s setting for this measurement. At any event that spectrum peak is only 30 uV rms. All in all, pretty good low amplitude results. See attached scope shot "FY3206S MDO3104 100kHz Sine Spectrum 5mVpp.png". :-+
The one bad thing with this generator is that the output amplifier can not drive a full 10 Vp-p across a 50 Ohm termination load with the set point set to 20 Vp-p. The specification trickily lists no load output as up to 20 Vp-p, which it does, and lists the output impedance = 50 Ohm, which it has, but the specs lists nothing about output amplitude with 50 Ohm load. By my measurements at all frequencies the amplitude maxes out around 7.5 Vp-p across 50 Ohm. It seems fully linear up to about 10 Vp-p set point. At 11 Vp-p set point the third harmonic for a 20 KHz waveform grows by 10 dB instead of the ideal expected 0.8 dB if the wave shape stayed constant and only amplitude grew by 11/10 gain. So, fully usable up to 10 Vp-p set point with 50 Ohm load while larger amplitudes are only useful with less load. :o :--
*This limited output drive capability explains why the 6 MHz 20 Vp-p set point power draw with and without 50 Ohm load can both be 3 W given the power doesn't report fractional Watts.
Just for fun I made an 2048 point waveform that is 10 sine cycles. This way when commanding 6 MHz you actually try to output 60 MHz. I would say using this technique you get usable output up to the full FY3224S product of 24 Mhz. Above 30 MHz the amplitude drops and the phase lag increases rapidly. Below are my test results:
Ch1 at 2.00 Vp-p (1.0 Vp-p into 50 Ohm) at 100 kHz for reference output amplitude:
(Phase measured relative to TTL sync pulse output)
Freq Amp Phase
MHz dB Deg
6.0 -0.5 -60
10.0 -1.5 -91
15.5 -3.1 -137
20.0 -4.9 -180
24.0 -6.9 -220
I even tried multiple cycles of a square wave and could get a usable but not "pretty" square wave up to 15 MHz. :clap:
I am guessing that if you pay the extra money for the FY3224S version you probably get the exact same HW with the FW letting the max frequency go up to 24 instead of the 6 for the FY3206S model I tested. Maybe there is an capacitor value difference in the DAC/output buffer amplifier low pass filter that allows higher bandwidth but I doubt it.
If there are any questions I will try to answer them. I will also update if further testing shows up anything interesting.
gby
Warning: On my Win 7 64 bit PC I did not install the old USB driver that was emailed to me. I just plugged the unit in and let Windows find the latest driver for me. When using the PC software it seemed to work. Until I tried to send an arbitrary waveform down to the unit. It erased the current waveform and then got stuck when trying to download the new data eventually reporting a Parity Error2. After trying many things, including learning that the USB connection is a Prolithic Technologies USB to serial PL-2303HX bridge chip, I finally beat Windows into submission to forget the new driver it had found and installed the old one emailed to me. In that configuration everything works fine. However, the USB to serial bridge chip is now obsolete and Prolithic states on their web site they will NOT update the driver for that chip for Win 8, 8.1. They recommend using their new pin for pin compatible chip instead. :-//
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Thanks for your extensive post GBY. I've bought a FY3206S myself (6MHz sine), reckoning the bandwidth would be 24MHz anyway. Looking at my FFT's for a square wave that seems to be the case, so no BW limiting on the models, probably just a firmware setting.
I am writing a Labview driver for it*), but have difficulty with the original software to upload wave forms to it: the software always bails out with an error (see screenshot). The software I received is "FY3200 PC software V1.0" and the FY3200 firmware says REV1.2.
I installed the serial driver that came with the package.
How did you get the waveform upload to work? Different SW version (if so, where can I download) or just the serial driver?
*) I've sorted most serial commands for this driver, but could not finish the waveform uploads. Your help is much appreciated!
FY3200s command set (work in progress):
a - get device id FY3206S\n
cf - query main channel freq. respose e.g. cf0000000050
cd - get main duty cycle - cd500
df - set secondary frequency e.g. df0001100000
bf - set main channel frequency e.g. bf
da - set secondary amplitude da08,00
ct - get main channel xx e.g. ct10
do - set secondary bias e.g. do02.1
bd - set main duty cycle e.g. bd668
dp - set secondary skew e.g. dp039
tn - set trigger cycles e.g tn0001000
ce - get counter frequency response e.g. ce0000000000
cc - get counter count repsonse e.g. cc0000000000
bc - clear counter
tt0 - trigger manually
tt2 - trigger channel 2
tt1 - trigger external
br0 - stop sweep
br1 - start sweep
br1.bf - set start frequency in cHz, e.g. br1\nbf600000000
bs1.bf - set stop frequency in cHZ, e.g. bs1\nbf600000000
bt - set sweeo time in sec 1-99, e.g. bt99
bs2.bt - set sweeo time in sec 1-99, e.g. bs2\nbt99
bm1 - linear sweep
bm2 - log sweep
bs - save settings in register nn e.g. bs00
bl - load settings from register nn e.g. bl00
dw0 - set secondary wave sine
dw1 - set secondary wave square
dw2 - set secondary wave triangle
dw3 - set secondary wave arbitrary 1
dw4 - set secondary wave arbitrary 2
dw5 - set secondary wave arbitrary 3
dw6 - set secondary wave arbitrary 4
dw7 - set secondary wave lorentz pulse
dw8 - set secondary wave Multi tone
dw9 - set secondary wave Periodic random noise
dw10 - set secondary wave ECG
dw11 - set secondary wave trapezodial pulse
dw12 - set secondary wave Sinc pulse
dw13 - set secondary wave Narrow pulse
dw14 - set secondary wave Gauss white noise
dw15 - set secondary wave AM
dw16 - set secondary wave FM
NOTES
first character:
d set secondary
c get main
b set main
t trigger
c counter
frequencies in cHz (centi Hertz)
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One thing I found of interest while working on the MHS-5200A upload is that the TTI manager software (http://tti1.co.uk/downloads/waveman-plus.htm (http://tti1.co.uk/downloads/waveman-plus.htm)) is a free download (I think you do have to register). It runs under Window (or, in my case, Wine) and lets you create waveforms in several formats. I wrote my uploader to handle those formats (the NRM one is pretty much what I was going to target anyway): https://github.com/wd5gnr/mhs5200a (https://github.com/wd5gnr/mhs5200a)
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Hi pdereus,
Unfortunately I have no suggestions for the error you are getting. Once I got the USB serial driver to be the old one things just seemed to work. For reference, in Windows device manager the working for me driver reports as:
Prolithic
7/31/2007
Ver 3.2.0.0
The actual driver file is:
C:\Windows\System32\drivers\ser2pl64.sys
dated 7/31/2007 with file size 90,112 bytes. My memory of the driver that Windows installed via Windows Update check was something like version 3.6 and for me with that driver the supplied vendor software worked for everything except arbitrary waveform download.
My unit also says ver 1.2 at power up and my PC software says ?'s when I do Help About so I assume it was trying to display Chinese characters and couldn't. The PC interface software install file that I ran is called: "FY3200PC SoftwareV1.3.exe" and is dated 5/22/15 with a size of 7,692,466. So, maybe it is newer. I have these versions working on Win 7 32 and Win 7 64. Unfortunately the file sizes are larger than the allowed 1000KB forum limit. I uploaded the zip file with the working driver, application I am using to dropcanvas.com. Since this is a no account "drop" it will expire in 3 days so download right away. Hope this solves your problem.
http://dropcanvas.com/p1ul6 (http://dropcanvas.com/p1ul6)
I am very impressed with your list of the serial commands. I thought about trying to reverse engineer the serial protocol but thought it would be too much work. So, I asked the ebay vendor fly-xy I bought from if he could get a serial protocol specification. He said not in English but did get me a Chinese document. I started with Google Translate and then I have been editing to clean it up as I go along. See attached. We are writing a Python GUI to automate some specialized setups. Between us maybe we can get this document cleaned up and complete. :)
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You've made my day! The v1.3 PC software you've uploaded did the trick, so I could get the protocol for waveform uploads (I made a Labview test that uploaded a 32x sinoid succesfully). Thanks also for the translated protocol. I may have missed some things in my reverse engineering.
My latest results are here (including the ARB wave form uploads).
a - get device id. response e.g. FY3206S\n
cf - query main channel freq. respose e.g. cf0000000050
cd - get main duty cycle - cd500
df - set secondary frequency e.g. df0001100000
bf - set main channel frequency e.g. bf0001100000
da - set secondary amplitude da08.00
do - set secondary bias e.g. do02.1
bd - set main duty cycle e.g. bd668
dp - set secondary skew e.g. dp039
tn - set trigger cycles e.g tn0001000
ce - get counter frequency response e.g. ce0000000000
cc - get counter count repsonse e.g. cc0000000000
bc - clear counter
tt0 - trigger manually
tt2 - trigger channel 2
tt1 - trigger external
br0 - stop sweep
br1 - start sweep
br1.bf - set start frequency in cHz, e.g. br1\nbf600000000
bs1.bf - set stop frequency in cHZ, e.g. bs1\nbf600000000
bt - set sweeo time in sec 1-99, e.g. bt99
ct - get sweep time xx e.g. ct10
bs2.bt - set sweep time in sec 1-99, e.g. bs2\nbt99
bm1 - linear sweep
bm2 - log sweep
bs - save settings in register nn e.g. bs00
bl - load settings from register nn e.g. bl00
Wave uploads
DDS_WAVE\0xa5 - initialized, response should be 'F'
DDS_WAVE\0xfx - erase memory n e.g. DDS_WAVE\0xf1 selects wf memory 1, response 'SE'
DDS_WAVE\0x0x - (e.g.DDS_WAVE\0x03 - upload data to memory x, response should be 'W'. After that 2048 bytes should be sent high byte first.You need about 5 ms between each byte to avoid buffer overruns
Wave form selection
dw0 - set secondary wave sine
dw1 - set secondary wave square
dw2 - set secondary wave triangle
dw3 - set secondary wave arbitrary 1
dw4 - set secondary wave arbitrary 2
dw5 - set secondary wave arbitrary 3
dw6 - set secondary wave arbitrary 4
dw7 - set secondary wave lorentz pulse
dw8 - set secondary wave Multi tone
dw9 - set secondary wave Periodic random noise
dw10 - set secondary wave ECG
dw11 - set secondary wave trapezodial pulse
dw12 - set secondary wave Sinc pulse
dw13 - set secondary wave Narrow pulse
dw14 - set secondary wave Gauss white noise
dw15 - set secondary wave AM
dw16 - set secondary wave FM
d set secondary
c get main
b set main
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Nice work guys! I so wanted to get back to my 24MHz model but was so busy for a month I just needed rest after that.
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pdereus,
I find connecting to the generator via USB cable a bit inconvenient since my computer is a fair distance from the lab bench. I have a JY-MCO bluetooth to serial converter that I am thinking about trying. (See http://www.dx.com/p/jy-mcu-arduino-bluetooth-wireless-serial-port-module-104299#.VaKQdLkmI0s (http://www.dx.com/p/jy-mcu-arduino-bluetooth-wireless-serial-port-module-104299#.VaKQdLkmI0s))
Since you have been reverse engineering the serial protocol I hope you have figured out the definitions for the J4 serial port connections. What I am getting at is, interior serial port connector J4 lists the pin out on the silk screen as:
5V
GND
TXD
RXD
Depending on whether you name the signals for the device (DTE) or where they go (DCE) TXD might be the generator output or the input. So, do you know if pin 3 labeled TXD is driven by the FY3200 generator or if it listens on that pin?
Second question, are the signals on these lines 3.3V level or 5V level?
Thanks for any clarity you can provide here.
gby
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Hi GBY,
I have to disappoint you here, as I did analyze the protocol at the software level (so at the Windows driver). I did not do any hardware level sniffing for this. I guess it's pretty easy to find out though: just put a scope to the pins and fire up the USB based software.
Fire commands that don't get a response (like changing the frequency) and you will be able to distinguish TxD from RxD (also with a multi meter :bullshit:)
Paul
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Are the 2 outputs completely floating (negative is not ground) and completely separate from each other (negatives not common)?
How easy is it to use arbitrary waveforms on the FeelTech FY3224S?
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I think all generators share a common potential reference between the channels (I am not aware of any multi-channel generators that have entirely isolated outputs). However, since (I think?) these units are powered by a wall-wart (or even a battery, if you wish), they must be floating relative to earth ground (as long as not connected via USB-usb may earth reference the device).
Some of these cheap units in this form factor have an internal power supply, and I do not know if those models are floating.
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The FY3200S series of generators have an internal supply and do not use a wall wart type supply. The power cord is only 2 wire and so the instrument does not get third prong ground/Protective Earth. This means that by definition the entire instrument floats with respect to earth. Like the previous poster listed all of the returns/negative on the BNC's for most instruments are shorted together. This includes this generator...to be sure I just used an Ohm meter and the BNC returns/negative terminals all are shorted together.
I would think that it is safe to float this generator 40-50 volts with respect to earth ground. Above that you will need to be very, very careful since you could get badly shocked by touching the buttons/knob and would certainly get shocked touching the return/negative of the BNC's. If you float the generator I would NOT connect the USB port since that port is not isolated. I would go with my idea of using a Bluetooth to serial module mounted inside the generator and then only adjusting/setting the generator via the PC software while the generator is floated.
gby
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pascal_sweden,
I find using the ver 1.3 software makes doing arbitrary waveforms very easy. The utility's built graphical screen to draw/create waveforms is functional but can not really be used for point by point precision. It is quite functional for a couple of standard waveform types but to get a precise waveform you need to calculate the points or use a data record recorded from a scope. I made a spreadsheet to make the 2048 point waveforms. I then just cut and pasted the points from the spreadsheet into the utility's "Text Window" tab and downloaded. This "Text Window" tab even has a button to plot the points to check that it looks right before downloading. Easy as can be.
gby
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What is the benefit of the MHS-5200P model with broadband-type option?
http://www.benl.ebay.be/itm/6-25MHZ-Power-Amplifier-Dual-Channel-DDS-Signal-Generator-NC-Arbitrary-Waveform-/281749051899?pt=LH_DefaultDomain_3&var=&hash=item41998d59fb (http://www.benl.ebay.be/itm/6-25MHZ-Power-Amplifier-Dual-Channel-DDS-Signal-Generator-NC-Arbitrary-Waveform-/281749051899?pt=LH_DefaultDomain_3&var=&hash=item41998d59fb)
I am confused about the difference between MHS-5200 (normal) and MHS-5200P (broadband-type).
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What is the benefit of the MHS-5200P model with broadband-type option?
http://www.benl.ebay.be/itm/6-25MHZ-Power-Amplifier-Dual-Channel-DDS-Signal-Generator-NC-Arbitrary-Waveform-/281749051899?pt=LH_DefaultDomain_3&var=&hash=item41998d59fb (http://www.benl.ebay.be/itm/6-25MHZ-Power-Amplifier-Dual-Channel-DDS-Signal-Generator-NC-Arbitrary-Waveform-/281749051899?pt=LH_DefaultDomain_3&var=&hash=item41998d59fb)
I am confused about the difference between MHS-5200 (normal) and MHS-5200P (broadband-type).
These P models seem to have power amplifiers at the outputs, to increase the power/current they can supply. The non-broadband model (claims it) can do 1A @ 80kHz, whereas the "broadband model" can do 300mA@5MHz. So it matters what you want to drive and at what frequency.
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If you float the generator I would NOT connect the USB port since that port is not isolated. I would go with my idea of using a Bluetooth to serial module mounted inside the generator and then only adjusting/setting the generator via the PC software while the generator is floated.
gby
I use this USB isolator in these sorts of situations, and it works quite well:
https://www.adafruit.com/product/2107 (https://www.adafruit.com/product/2107)
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What is the benefit of the MHS-5200P model with broadband-type option?
http://www.benl.ebay.be/itm/6-25MHZ-Power-Amplifier-Dual-Channel-DDS-Signal-Generator-NC-Arbitrary-Waveform-/281749051899?pt=LH_DefaultDomain_3&var=&hash=item41998d59fb (http://www.benl.ebay.be/itm/6-25MHZ-Power-Amplifier-Dual-Channel-DDS-Signal-Generator-NC-Arbitrary-Waveform-/281749051899?pt=LH_DefaultDomain_3&var=&hash=item41998d59fb)
I am confused about the difference between MHS-5200 (normal) and MHS-5200P (broadband-type).
These P models seem to have power amplifiers at the outputs, to increase the power/current they can supply. The non-broadband model (claims it) can do 1A @ 80kHz, whereas the "broadband model" can do 300mA@5MHz. So it matters what you want to drive and at what frequency.
Can you highlight the application area for these frequency power amplifiers?
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Can someone do a similar teardown on the FeelTech FY3224S, and identify if the same issues are present regarding harmonic distortion, or if the output stage design is better, and results in better waveform signals?
https://www.eevblog.com/forum/testgear/mhs-5200a-function-generator-teardown-review-reverse-engineering/ (https://www.eevblog.com/forum/testgear/mhs-5200a-function-generator-teardown-review-reverse-engineering/)
In this video they reverse engineered the analog front end of the MHS-5200A to track down the source of the harmonic distortion that happens at higher output amplitudes and higher frequencies.
They identified that the supply voltage to the final output stage (an AD812 dual op-amp) is not high enough (backed by the datasheet of the AD812) and that this is causing clipping/distortion.
When the supply voltage is increased from +9V,-9V to +15V,-15V, there is still some harmonic distortion, but the output waveform is looking better.
Maybe the FeelTech FY3224S and the MHS-5200A are the same underneath, or very similar. Just that on its own would be good to know.
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Pascal_Sweden,
I know that the supply is not 9V on the FS3200xx. The internal pictures clearly show the power supply labeled +/- 12V for the analog supplies. Also, when open circuited the output easily goes to 20 Vp-p or +/-10V which means that the supply rails on the analog output stage must be > than 10V.
Based on my measurements it is pretty clear that the output analog buffer is current limited at just about 70 mA 0-p. Into a 50 Ohm load this max current limits the output to about 7.5 Vp-p matching my measurements. I highly suspect they limited the current to only 70 mA to limit the power consumed and dissipated in the analog output buffer. Could also just be a limit of the analog buffer IC they chose.
I have thought about changing the output buffer to have more output current and more capability. That probably would require changing the buffer IC and adding more heat sink. We might get lucky that the analog buffer IC under the heat sink can do more current with more heat sinking but until someone takes the unit completely apart, removes the heat sink we don't know what IC they are using.
For a cheap generator the harmonic distortion is actually pretty low below 5Vp-p amplitude into 50 Ohm. At 100 kHz I measured only 0.56% THD at 20Vp-p output with an open circuited load.
gby
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A friend of me has a Rigol SDG1025. He paid about 300 EUR for it!
I was showing him the link to the FeelTech FY3224S signal generator, but he was not impressed about the build quality, compared with his nice looking Rigol SDG1025. Of course I fully understand why :)
As the design could not convince my friend, I told that the specs seem quite good, given that it only costs 100 EUR.
Then I was thinking. Is the Rigol SDG1025 really that much better? And how much better?
Here is the data sheet from the website:
http://www.siglent.com/2014EnglishWebsite/Documents/Datasheet/SDG1000_DataSheet_DS02010-E07A.pdf (http://www.siglent.com/2014EnglishWebsite/Documents/Datasheet/SDG1000_DataSheet_DS02010-E07A.pdf)
I don't have the full specifications from the FeelTech FY3224S at hand, so can't do the comparison.
And then who knows if the specs from FeelTech really tell the truth.
But if we assume that the specs from Siglent are correct, then it should be possible to do a comparison between the two tables, and summarize the weaknesses/strengths/equalities among the Siglent SDG1025 and the FeelTech FY3224S.
Would you mind taking up this homework for the community? :)
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Rigol SDG1025
Huh???
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Yes, both are around 25MHz.
To know how good the Siglent is, and how bad the FeelTech is, relatively :)
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I have this temptation to write a perl module to interface with this and put it on CPAN. If there would be a practicality for a command line interface to the unit on a computer or over a network.......
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I started making a few movies doing some basic tests with this device. Ive noticed that for the frequency counter the reliable reading seems to be just above 1.5 volts at least at 455khz using a sine wave.
https://www.youtube.com/watch?v=ClbJPD1L8Wg (https://www.youtube.com/watch?v=ClbJPD1L8Wg)
Also, I was curious, as it was mentioned that the device has an amplitude modulated waveform. I may be a bit confused here, however I ran the FY3200 at 455KHZ 2V AM waveform in channel 2 and my RF generator using the same setting in channel 1. See the video and perhaps explain to me what im missing. Im thinking that the carrier is 455KHZ but the signal injected into the carrier is an entirely different frequency all together
https://www.youtube.com/watch?v=2u58chreleQ (https://www.youtube.com/watch?v=2u58chreleQ)
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The lower trace on your 'scope looks like a properly-modulated waveform. What is the modulating frequency? I'm guessing it's around 57 KHz as there are about 8 carrier cycles inside of each modulation cycle.
What you're seeing in the top trace when you decrease the sweep frequency is just an artifact of sweep frequency vs. carrier, not actual modulation.
EDIT: On second thought, the top waveform might actually be AM, just not 100% modulation like the bottom. What was the initial horizontal sweep speed before you changed it in the video? It looks like the modulation frequency on the DDS generator is the same as the carrier frequency on the analog generator. What do you have the other (SF?) frequency set to on the DDS?
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Im wondering, has anyone used the software to define a waveform that replicates the injection of a waveform onto a modulated AM carrier?
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The lower trace on your 'scope looks like a properly-modulated waveform. What is the modulating frequency? I'm guessing it's around 57 KHz as there are about 8 carrier cycles inside of each modulation cycle.
What you're seeing in the top trace when you decrease the sweep frequency is just an artifact of sweep frequency vs. carrier, not actual modulation.
EDIT: On second thought, the top waveform might actually be AM, just not 100% modulation like the bottom. What was the initial horizontal sweep speed before you changed it in the video? It looks like the modulation frequency on the DDS generator is the same as the carrier frequency on the analog generator. What do you have the other (SF?) frequency set to on the DDS?
Yes the top is from my RF generator which is AM. The frequency knob was set to 455khz and checked on the frequency counter, the voltage was set so both channels would have the same amplitide. As for the injected signal produced by the RF generator, I cant be sure what the frequency is as the amplitude and frequency variation are set by pots with a screw driver. I will check to see if I can remove the 455khz from the output and see what the injected frequency is
UPDATE:
It seems that as per the manual, when set to internal modulation, the audio input jack will have the modulated frequency on it for measurement and setting. I will retest tomorrow and provide the figures
http://site.ldbepurchase.com/Manuals/TSG17.pdf (http://site.ldbepurchase.com/Manuals/TSG17.pdf)
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I was able to use the audio input jack to set the AF to 500hz. The peak to peak amplitude showed about 6 volts on the auto output. The mod-level POT had little effect on the amplitude.
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I have been working with my FY3206S generator some more and noticed that it does not change frequency smoothly. When using the knob or commanding over the USB connection when you ask for a new frequency the generator output pauses/holds the voltage and then continues on with the new frequency. It seems to take about 1.35 mSec for the frequency to update and during that time the output values seem to be held at DC values. See attached scope photo "Step Changes To Frequency Detail.png" for an example of what I am seeing.
If you use the built in sweep function the frequency changes smoothly as you would expect. Unfortunately, I am trying to make 0 and 90 Degree synchronized sine waves sweeping up in frequency and the FY3200 built in sweep mode only works on CH1 and CH2 stays fixed/not sweeping. In sweep mode it does not seem to matter matter whether the System menu setting "Freq CH1=CH2" is set or not CH2 does not sweep.
I did use a Python script to command the frequency to step every 12 mSec and the result is that I get 0, 90 sines with the frequency sweeping up but with a 2.7 mSec glitch at each step (one 1.35 mSec of CH1 and one 1.35 mSec for CH2). So, whatever mechanism the FY3200 uses to change set point frequency it does not do it in a step manner. It seems to set frequencies to 0 and then to the new set point. See attached scope photo "Sine Ch2 Sync Ch1 Serial Sweep Freq.png" to see the Python script stepping the frequency with two channels synchronized in frequency.
Does anyone know if more expensive $300 generators such as Rigol DG1022/Siglent SDG1025 or the next step up $600 Rigol DG1032Z/Siglent SDG5082 would be able to sweep two channels while staying locked at 0, 90 Degree with no glitches??? That is, the frequency changes smoothly and the 90 phase relationship stays in synch at each frequency change?
gby
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I just checked for this behavior on my MHS-5200A (60 - 80€ 6-25Mhz 8bit Signal-Gen from ebay) and got an immediate response to changing the frequency as you can see in the attached screenshots.
How did you measure this btw.? I used Roll-Mode and then switched between 1 and 2 khz on the generator.
So if you can live with the distortion the MHS-5200A introduces into the signal at higher amplitudes, you don't necessarily have to pay several hundred bucks^^
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have anyone else confirmed the mhs-2300a bug does/does not exist in the FeelTech FY3224S or MHS-5200A ?
set CH1 to 10khz sine, CH2 to 10khz sine. Phase should be perfectly locked, and lissajous should be stable. Both are integer ratio of the master clock.
set CH1 to 10khz sine, CH2 to 20khz sine. Phase should be perfectly locked, and lissajous should be stable. Both are integer ratio of the master clock. But in mhs-2300a, CH2 has phase shift errors and CH2 is not stable. <- bug!!
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SaabFAN, to measure the frequency change from the knob or from the PC adjustment I just set the scope to take lots of points and then randomly hit the stop button on the scope while spinning the knob/stepping the frequency via a program. I then zoomed into the shot to find the frequency change moment. Nasty bug/deficiency to be sure.
Usagi, when CH1 and CH2 on the FY3200 are set to be locked they are frequency and phased locked. If I set the phase to be 90 Deg apart they are locked 90 Degree apart. Since you mentioned lissajous I just set up the scope with 1 kHz, equal amplitudes and got a perfect circle with the scope set to X versus Y. I then set slightly unequal amplitudes and the oval from the un-equal amplitudes did not precess at all. Whatever the bug you mention that the MHS-2300a has the FY3200 does not have that problem.
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Usagi, when CH1 and CH2 on the FY3200 are set to be locked they are frequency and phased locked. If I set the phase to be 90 Deg apart they are locked 90 Degree apart. Since you mentioned lissajous I just set up the scope with 1 kHz, equal amplitudes and got a perfect circle with the scope set to X versus Y. I then set slightly unequal amplitudes and the oval from the un-equal amplitudes did not precess at all. Whatever the bug you mention that the MHS-2300a has the FY3200 does not have that problem.
try CH1 1khz CH2 2khz and see if it precesses.
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I have just tried the 1 khz 2khz check on my FY3224S using my DS1054Z scope on CH1 and Ch2. Observing the display in XY there is a slow drift in the lissajou display. A complete cycle of the the difference takes just under 3 minutes (about 2 secs under). Also the scope frequency meter (on CH1) seems to cycle between 999.999 hz to a minimum of 999.997 hz. Just to be sure I checked with both sources set to 1khz but one channel set to a 45 degree phase difference to make it easier to watch. There was no noticeable drift under this circumstance although the frequency counter on the scope CH1 still showed a drift as mentioned earlier.
Interesting.
John
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I repeated this test for 10khz 20khz and could not see any drift on the lissajou. However at 100hz 200hz it was the same drift rate as found at 1khz 2khz.
John
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Whoops, I missed the suggestion of doing two different frequencies, e.g. the suggested 10 kHz and 20 kHz. I just tried 1 and 2 KHz and see what you mean. Given the simple nature of these generators and given how the frequencies are made I can see how two different frequencies would be an issue. Probably some kind of truncation of the math used to set the frequencies.
If you need to have two different simple integer ratio frequencies that stay absolutely locked, then I would use one as wave type sine and one as wave type arb with multiple sine cycles in the arb. For example, set CH1=CH2 frequency mode, program Arb for 2 sine cycles per 4096 pints (for the FY3200). Then select sine wave for one and the 2 cycle Arb sine for the other. Now you have perfectly locked signal with 2:1 frequency ratio. I just tried this on the FY3200 and it works fine. You can even change the phase value to change the relative lock.
Of course, if this mode is just a test of the device's capabilities, then yes yet another weakness has been found. But, what do you expect for a generator costing 10-40x less than quality ones :-DD.
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If the DDS is implemented in the textbook fashion, off of a common clock, I can't think a good reason for the two channels to not be phase locked if one frequency is an integer multiple of the other.
https://en.m.wikipedia.org/wiki/Numerically_controlled_oscillator
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You would that textbook math for DDS when both frequencies are integer divisors of the main clock and are in an integer ratio to each other would yield the expected ideal result. However, many (most?) actual generators use a fixed binary length to the phase word to cover one complete/360 Deg waveform cycle. This means that if you are not careful there will be non-integer values required to get the specific frequency you ask for. In addition, the FW that sets the digital logic accumulation rate is finite precision arithmetic and rounding/truncation is involved. So, you might end up off by a small amount.
Consider a made up example similar to the FY3200. I say made up because we don't know the exact FY3200 inside details.
clock = 250 MHz = accumulation clock
minimum frequency = (250 MHz)/(2^36) = 0.003638.... Hz
>>> 36 bit accumulator clocked at 250 MHz with the top bit representing 180 electrical degrees.
To DDS 1.000 kHz the input word to the accumulator would need to be:
(2^36)*(1 KHz/250 MHz) = 274877.907 which rounded to an integer = 274878
To DDS 2.000 kHz the input word to the accumulator would need to be twice that or 549755.814 rounded to 549756
The ratio of 549756/274878 is exactly 2 and should work as desired. But, if the FW did truncation of the result instead of rounding you get 549755/274877 = 2.000003638 which will yield a lissajou that will precess and take about 5 minutes to make a complete cycle.
Note that this particular example does have an exact 2:1 solution. But, there are numbers where the proper rounded value for the higher frequency would be an odd integer and when you cut it in half and round you will not get an exact integer ratio. Basically, I am saying that even in a well implemented textbook DDS system it depends on the detailed number on whether two frequencies that you want to be 2:1 or 3:1 or whatever ratio can actually be exactly that ratio. Basically I am not convinced that this test proves there is any design flaw in the FY3200.
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Yeah, I worded that wrong--I can't see a good reason for there to be a non-cyclical phase difference between the two waveforms.
However, it does depend on the implementation, and how they are handling truncation of the phase accumulator.
I would expect the waveforms to sync back up with a predictable period.
However, as you say, there should be frequencies where this is not the case and they remain phase locked, if done properly.
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Dadler, that is exactly what the FY3200 generator does. When you select 1.00 kHz and 2.00 kHz the Lissajous pattern very slowly precesses and eventually repeats in a cyclic fashion. As JohnPen reported 10.0 khz and 20 kHz does not precess and stays phase locked. Locked or precessing just depends on the details of the frequencies selected.
So, I conclude that there is no bug in the FY3200 for setting frequencies and holding them. The issue is inherent in all DDS generators because of the finite precision frequency input to the phase accumulator. As I mentioned before, if you really need 2:1 or 3:1, etc exact frequency ratios that are reliably phase and freqeuncy locked put a 2 or 3 or whatever cycle waveform in the FY3200 4096 point Arb wave shape. Then no matter what frequency you select they stay frequency and phase locked.
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Maybe Im missing something..... Does anyone know where or how to set the trigger output on the sweep function to go to the trigger on the scope?
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I haven't found a way to do it as there is no trigger output. I tried to persuade CH2 to do something and it will trigger on say 10 sec intervals etc but the output unfortunately doesn't relate the timing of the sweep output. Presumably one could reverse engineer to add a trigger output but currently I am leaving well alone as I have only recently purchased my unit.
John
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- Set the frequency to 1999.29994 KHz
- Press the blue knob in (changes display from KHz to MHz)
- Power down the unit and wait 15 seconds
- Profit! (Sine wave capability extends to 24 MHz)
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- Set the frequency to 1999.29994 KHz
- Press the blue knob in (changes display from KHz to MHz)
- Power down the unit and wait 15 seconds
- Profit! (Sine wave capability extends to 24 MHz)
How did you ever figure this out?
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- Set the frequency to 1999.29994 KHz
- Press the blue knob in (changes display from KHz to MHz)
- Power down the unit and wait 15 seconds
- Profit! (Sine wave capability extends to 24 MHz)
Do you know of a similar way to "hack" the MHS-5200A?
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How did you ever figure this out?
I wish I could take credit for it, but actually I heard about it from a friend of a friend. ;)
Do you know of a similar way to "hack" the MHS-5200A?
Nope, sorry mate, but I'll ask around. :)
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I figured out the riddle regarding amplitude modulation first discussed in reply #40. There is no way to amplitude modulate one signal with another on this generator. All of the presets, PRE1-PRE10, are simply stored waveforms. PRE9 happens to be a waveform where the modulating frequency is 1/16 the carrier frequency. The only thing you can control is how often this waveform is "played out." So, setting the frequency to 10 KHz gives you a 160 KHz carrier modulated with a 10 KHz signal.
In the good news department, the TTL outputs on the back are driven by a 74LVC14 Schmitt trigger operating on 3.3 V power. This means you have a signal with sub-nanosecond rise times that can drive 3.3 or 5 V logic. Furthermore, if you set the waveform type to square, the duty cycle on the TTL outputs will follow what you have set on the front panel. So, it's a lot more useful than just a sync output.
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What I really needed was a trigger signal for the sweep generator........
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After applying the sequence provided in quantalume's post yesterday to my FY3206S 6 MHz generator I see that ALL the wave shapes can now be turned up to 24 MHz. The official manual/specs list 6 MHz max for square, triangle, arbitrary no matter which version. So, this hack has unlocked the frequency setting for everything up to 24 MHz :clap:
Of course, the generator does not have enough bandwidth to do a good job for square or triangle at 24 MHz. However it is definitely usable beyond 6 MHz. I tried a square at 6.6 Vp-p (with 50 Ohm termination 3.3V p-p for a logic signal) and found usable results beyond 6 MHz.
Square:
Set 6.6 Vp-p and scope has 50 Ohm termination
0.1 MHz 3.26 Vpp (Reference) great square shape
1.0 MHz 3.24 Vpp (- 0.6%) good square shape 26 nSec rise time
6.0 MHz 3.22 Vpp (-1.2%) OK square shape 24 nSec rise time flat top for 90 degrees (ideal would be 180)
10.0 MHz 3.14 Vpp (-3.7%) Usable square shape 24 nSec rise time barely any flat top
15.0 MHz 2.68 Vpp (-18%) Barely usable, basically a sine wave shape
24.0 MHz 1.68 Vpp (-49%) Unusable, basically a sine wave
See below oscilloscope shot of 10 MHz square. This scope shot shows the trigger wave and CH1 out. The phase lag from trigger to CH1 out is 14 nSec or 50 Deg and probably all of this is from the output low pass filter. As quantalume commented the trigger signal is quite fast with about 2 nSec rise time (at least on my 200 MHz analog BW scope).
I also tried 10 MHz square with duty at 33% and the amplitude was 2.91 Vpp which is still quite usable.
I quickly checked the sine shape at 24 MHz and found the amplitude to be down by 1.58/3.24 = -6.2 dB and it lags the trigger by 25.6 nSec/220 Degrees. This data matches the results when putting 4 sine cycles in an Arb waveform and running at 6 Mhz rep rate for 24 MHz out that I reported earlier. This confirms to me that this FY3206S generator output filter is causing the limit.
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I did a video on this to test my new scope..... while i did not read the maximum frequency limit of 6mhz for non-sine waves, I still thought the output was crappy even a 6mhz
(https://lh6.googleusercontent.com/-CfQ6qauPw-c/Vgx5W6Hxe_I/AAAAAAAAB-8/qqvInX1EZK8/w912-h615-no/Screen%2BShot%2B2015-09-30%2Bat%2B8.05.07%2BPM.png)
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I would like to isolate the circuit that sends the signal for the sweep to reset and make a usable pulse from it for a trigger for my scope.
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Do you know of a similar way to "hack" the MHS-5200A?
Nope, sorry mate, but I'll ask around. :)
an mhs-5200a hack would be ace :-+
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Looks like the sweep resets in the processor..........
I searched for any artifacts on the board that I could use as a trigger, but no dice...
anyway, with the 5072P at least theres an FFT.
https://www.youtube.com/watch?v=f__aDOZ0o14 (https://www.youtube.com/watch?v=f__aDOZ0o14)
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jcrubin,
Your 6 MHz square wave signal looks significantly worse than on my FY3200. The picture you show has a fair bit of ringing and overshoot while on mine the signal has essentially none. See attached scope photo from a 200 MHz Tektronix connected via BNC cable with scope set for proper 50 Ohm termination at 6 MHz at FY3200 setting of 4 Vpp. Essentially no overshoot, no ringing, and nice smooth rise and fall times within the 21 nSec rise time limit. I also attached a 10 Vpp 6 MHz result which is almost as good but has a little more tilt on the flat bottom.
The scope photo you show measures 10 Vp-p ignoring the overshoot/ring. If you have the scope set for 50 Ohm termination then the FY3200 is set for 20 Vpp and the output buffer is current limiting and going non-linear which can explain the poor wave shape. See my earlier test results post on this generator to see the output waveform current limit issue in more detail.
If you don't have the scope input at 50 Ohm termination, then you will get bad ringing over the cable which could cause overshoot and distortion.
I suggest trying your test again with the FY3200 set to 10 Vpp, BNC cable from generator to scope, scope has 50 Ohm termination right at it. If you don't have 50 Ohm termination available with a good BNC cable, then try the oscilloscope probe right at the FY3200 BNC output with no cable. I think you will find the waveform quality much better than you show and like the ones I attached.
On your quest to find a trigger signal for the sweep function I think you are going to be out of luck. The sweep function is done entirely in the software, FPGA in these generators and thus unless they specifically design it to have a sweep trigger signal then it will only exist inside the chips and not on a pin.
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A substantial amount of testing was done yesterday, and the signal did improve with the correct 50 termination using bnc cable
ive posted my results in the 5072P thread below
https://www.eevblog.com/forum/testgear/hantek-dso5072p-thread-not-the-bandwidth-hack-thread/new/?topicseen#new (https://www.eevblog.com/forum/testgear/hantek-dso5072p-thread-not-the-bandwidth-hack-thread/new/?topicseen#new)
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- Set the frequency to 1999.29994 KHz
- Press the blue knob in (changes display from KHz to MHz)
- Power down the unit and wait 15 seconds
- Profit! (Sine wave capability extends to 24 MHz)
...and of course you can downgrade it again (for whatever reason):
Set the frequency to 1999.09996 kHz (or 1999.19992 kHz)
and follow the rest of quantalume's steps and you have a different model :clap:
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Some FFT testing of the waveforms
https://www.youtube.com/watch?v=wZoGWvYUl7Y (https://www.youtube.com/watch?v=wZoGWvYUl7Y)
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I have recently bought an FY3224S frequency generator and it arrived without any documentation or software. Although I was able to download the manual from the web I have been unable to find any software. Does anyone have any such software or know where I can get hold of it?
Many thanks!
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I just ordered one of these bad boys after reading through this thread and seeing that it is not a total POS. It's incredibly cheap for what it is.
@Pete69Walton: if you still haven't found a copy of the software when I get mine I'll upload it to the cloud.
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If anyone wants to see how the FY3224S performs at higher frequencies, I've posted a bunch of photos on my blog including a few comparisons with a Rigol DG1022U:
http://www.dalbert.net/?p=322 (http://www.dalbert.net/?p=322)
Amplitude accuracy is good up to 3MHz and then starts to drop off. An unloaded 24MHz sine wave configured for 1v amplitude measured 210mv p-p. However, it is still a decent looking an stable sine wave.
Square waves look good at 1MHz and then start to degrade. Still serviceable at 5MHz, but above that, the edges are lost and jitter becomes excessive. It's only rated to 6MHz for square waves so that's probably fair.
I also tested the frequency counter function and it was able to count to its rated 100MHz with a +7dBm signal (lower signal levels reduce the frequency...I was only able to reach 47MHz at 0dBm). With a strong (+13dBm) signal, it was able to accurately count as high as 225MHz!
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Should I take consideration when connecting the unit to an amplifier input with a 470K input impedance. The feeltech is 50 OHM.
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I wanted to experiment with using the FY3200S to characterise a filter, but ran into the same sweep generator issue that jcrubin did. So I started hacking up something in python to generate better sweeps, but that's unfortunately not going to work. When you change the frequency it resets to the start of the phase so it is not possible to get clean transitions between frequencies.
I couldn't find any existing code posted to control the FY3200S so I took my hacky mess and threw it up on github at https://github.com/stupid-beard/pyFY3200S
This was hacked together in a couple of hours at the weekend so it's really, really hacky and more than a little shitty right now. It's enough to control the basics but I didn't bother with implementing sweeps due to the aforementioned issue. I'll flesh it out further and tidy it up a bit at the weekend when I have more time.
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I would like to isolate the circuit that sends the signal for the sweep to reset and make a usable pulse from it for a trigger for my scope.
How about triggering on the width of a pulse? That should make the scope trigger on the start of the sweep.
Edit: I'll clarify... at the start of a sweep (or end) the sine wave is wider/narrower. The width of the sine wave can be set as a trigger condition in most DSOs. This allows to trigger at a certain point in the sweep.
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Every single output and input is controlled by the processor, as i'm lead to believe. This tells me that a trigger could be programmed on an output if the firmware were updated to accommodate such a function.
Has anyone attempted yet to read out the firmware code to decipher it?>
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- Set the frequency to 1999.29994 KHz
- Press the blue knob in (changes display from KHz to MHz)
- Power down the unit and wait 15 seconds
- Profit! (Sine wave capability extends to 24 MHz)
Call me dumb & stupid but this trick doesn't work on the one I have here.
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Call me dumb & stupid but this trick doesn't work on the one I have here.
Which model do you have?
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Call me dumb & stupid but this trick doesn't work on the one I have here.
Which model do you have?
It is the 6MHz model
Sitcker says: FY3200S
Unit says: FY3206S Rev. 2.0
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Still no way to uphack the newer models? I have tried once more but no luck.
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I have recently bought an FY3224S frequency generator and it arrived without any documentation or software. Although I was able to download the manual from the web I have been unable to find any software. Does anyone have any such software or know where I can get hold of it?
If you still need the software, I've uploaded it to google drive. Get it via this link:
FY3200S Software (https://drive.google.com/open?id=0B0_3Cv9W53YJZGw3Q0hkT01HQ2s)
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Well bugger! The disc the unit came with is defective. The English version of the software cannot be read from the disc.
A quick check of the built-in waveforms on a Rigol DS1054E looked fairly pleasing. Basic sine waves are good to 20MHz, and the rest more or less as one would expect with a ~20MHz BW limit. But damn they've screwed me with the software. If anyone would care to upload the 7MB rar or exe file named:
FY3200 PC Contrl Software V1.4Setup
(or any English version of the software) it would be much appreciated.
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If anyone would care to upload the 7MB rar or exe file named:
FY3200 PC Contrl Software V1.4Setup
Just got my FY3224 20 minutes ago. I put the CD to the web, your file seems to be here:
<http://shor.ch/software/FY3224S-arb_gen/FY3200S%20User%20Guide/PC%20Software/>
hope this helps, Daniel
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Awesome! Thanks!!
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I took a look at the spectral purity of the FY3224S (how clean a signal it generates) and posted some pictures of the close-in spurs and harmonics to 200MHz on my blog reviewing it. The pics are near the end so you'll have to scroll down a bit. The blog review is here: http://www.dalbert.net/?p=322 (http://www.dalbert.net/?p=322)
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How does one get the s/w to work with Win 10?? PL2303 etc does not communicate.
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I took a look at the spectral purity of the FY3224S (how clean a signal it generates) and posted some pictures of the close-in spurs and harmonics to 200MHz on my blog reviewing it. The pics are near the end so you'll have to scroll down a bit. The blog review is here: http://www.dalbert.net/?p=322 (http://www.dalbert.net/?p=322)
Cool! It would be interesting to have a look inside, especially the output opamps etc.
What was the dB scale on the harmonics pictures?
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How does one get the s/w to work with Win 10?? PL2303 etc does not communicate.
If you can't get it working, the USB to serial thing is a separate board and can be easily swapped with any alternative you may have laying around. Not an ideal solution, but might help.
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I took a look at the spectral purity of the FY3224S (how clean a signal it generates) and posted some pictures of the close-in spurs and harmonics to 200MHz on my blog reviewing it. The pics are near the end so you'll have to scroll down a bit. The blog review is here: http://www.dalbert.net/?p=322 (http://www.dalbert.net/?p=322)
Thanks for this! I'll be very interested to see what conclusions you come to regarding whether or not performance can be improved by modifying the output device and/or filter. The rotary encoder could use an upgrade too.
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i received 12 mhz version from taobao - 24mhz trick doesn't work too (Ver2.0 on start display)
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I think it's funny that you mention that it will only do 6MHz beyond a sine wave...that's better than the Siglent except on the square which is 10MHz, and it isn't the best looking square at that! 6MHz for an arbitrary waveform is actually very good. I can't see how the Siglent has much better specs at all really.
Risetime?
The Siglent SDG 1025 specs I found on the Net list . . .
25MHz; 2 channels; 125MSa/s; wave length: 16Kpts
Here's some of the FeelTech FY3224S Specs from the Ebay Listing . . .
?Built-in arbitrary waveform with 250 MSa/s sampling rate.
?4 downloadable 2048 dots arbitrary waveform memories
?With 12 bit wide waveform generator
?Each function can be adjusted by host computer.
?Preinstalled 14 common waveforms.
?High frequency accuracy: magnitude 10?6
?High resolution: Full range frequency resolution can be 10 mHz.
?Both main and subsidiary wave duty cycle are adjustable separately (0.1%~99.9%?.
?All range continuously adjustable, digital directly setting.
Model
FY3224S
Sine wave frequency range
0Hz~24 MHz
Square wave frequency range
0Hz~6MHz
Triangle wave frequency range
0Hz~6MHz
Arbitrary wave frequency wave
0Hz~6MHz
I pulled the Trigger on this FY3224S DDS AW Function Signal Generator & also a Rigol DS1054Z Scope . . .
Should have the FY3224S within 10-Days & the Rigol Scope by this Wednesday . . .
It's been Years since my Trusty Old TekTronic RM43 35Mhz Tube Scope / 19" Rack Mount has been seen & My old HealthKit 1-100K Sine / Square Wave generator disappeared in an ancient move . . .
Will be kind-of-fun to get a more "Modern" test development electronics bench setup going . . .
This is My 1st Post Here . . . Cheers from Orion12
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I took a look at the spectral purity of the FY3224S (how clean a signal it generates) and posted some pictures of the close-in spurs and harmonics to 200MHz on my blog reviewing it. The pics are near the end so you'll have to scroll down a bit. The blog review is here: http://www.dalbert.net/?p=322 (http://www.dalbert.net/?p=322)
Nice FY3224S Review & Photo Examples Dave . . .
Seeing your review & digging around a bit was all I needed to Pull the Trigger @ $79.55 with Free Shipping . . . I don't believe I'll loose sleep over my missing HealthKit .1-100K Sine / Square Generator ( Which did Serve Me Well for Many Years & was a Fun Build ) . . .
Also Finally Pulled the Trigger for a Rigol DS1054Z from TechEdu.com for $379.05 with Free Shipping . . . If I remember correctly my old TekTronic RM43 / 35Mhz Tube 19" Rack Mount Scope cost about the same USED from United Surplus of Seattle in 1976 . . . Sorting Out the "Best" Deal in Scopes was a Really Tuff task in this Very Competitive Marketplace . . . The relatively easy hack to 100Mhz with 4-Channels continued to best the competition in the end . . . I would have liked getting into a 2M/Sample/Sec scope & Or Faster than 30K / WaveFrame updates but just couldn't find this ANYWHERE Close to $600 with 4-Channels . . . ( Maybe I missed something )
btw . . . How's the USB Connected Software Work with the FY3224S ?
Thanks Again for Your Data Intensive Review . . . Cheers from Orion12
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i received 12 mhz version from taobao - 24mhz trick doesn't work too (Ver2.0 on start display)
I have version 1.2, and it worked there. They must have made a firmware change somewhere along the way.
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I took a look at the spectral purity of the FY3224S (how clean a signal it generates) and posted some pictures of the close-in spurs and harmonics to 200MHz on my blog reviewing it. The pics are near the end so you'll have to scroll down a bit. The blog review is here: http://www.dalbert.net/?p=322 (http://www.dalbert.net/?p=322)
Cool! It would be interesting to have a look inside, especially the output opamps etc.
What was the dB scale on the harmonics pictures?
10dB/division
I meant to post some spectral purity/harmonic comparisons with the Rigol DG1022...I'll try to get to that soon.
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Ive repaired my HP 331A, power supply and tested the functionality of the unit with the waveform generator
(https://lh4.googleusercontent.com/-erdZ_KrhDU8/VmZGPkvfFTI/AAAAAAAAClU/rQk3Sr2OlkA/w1157-h868-no/15%2B-%2B1)
The following photos are before any calibration, and just testing the operation and controls of the unit. Though not calibrated, feel free to provide any thoughts
on the results.....
Coax to unshielded alligator clips, no 600ohm terminating resistor
THD = .21% at 1KHZ 1V
(https://lh6.googleusercontent.com/-0vp_Wh8yPQs/VmZGPsiLIFI/AAAAAAAACk8/MAmQSU73mdE/w1157-h868-no/15%2B-%2B4)
THD = .205% at 5KHZ 1V
(https://lh4.googleusercontent.com/-d7evRRwXIss/VmZGPj8F48I/AAAAAAAAClE/29cTtHxRhKU/w1157-h868-no/15%2B-%2B7)
THD = .215% at 10KHZ 1V
(https://lh6.googleusercontent.com/-0yVycF4rpwE/VmZGPnD9-mI/AAAAAAAACls/c07eip5S8eI/w1157-h868-no/15%2B-%2B8)
THD =.315% at 20KHZ 1V
(https://lh4.googleusercontent.com/-e_4r78HsORg/VmZGPp5zz-I/AAAAAAAACkk/hPp-eEB75RM/w1157-h868-no/15%2B-%2B9)
THD =1.2% at 40KHZ 1V
(https://lh4.googleusercontent.com/-8fa_a01Khd4/VmZGPrstbOI/AAAAAAAAClM/Adb9GZTYm0g/w1157-h868-no/15%2B-%2B10)
THD =2.2% at 50KHZ 1V using x10K * 5
(https://lh6.googleusercontent.com/-ru-XoZGgzws/VmZGPgmBuFI/AAAAAAAAClk/U9kVtMCbh6c/w1157-h868-no/15%2B-%2B11)
THD =2.2% at 50KHZ 1V using x1K * 50
(https://lh4.googleusercontent.com/-_IW6SNicQTM/VmZGPlLnQtI/AAAAAAAAClw/_NyHflNhPKY/w1157-h868-no/15%2B-%2B12)
THD = 3.6% at 60KHZ
(https://lh6.googleusercontent.com/-8z8oXE-LlVE/VmZGPviLP_I/AAAAAAAACl4/RL0-72LQ7jo/w1157-h868-no/15%2B-%2B13)
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Movie of the HP331A repair along with a FY3200s harmonic distortion shootout
https://www.youtube.com/watch?v=NJxPiqW5Ww4 (https://www.youtube.com/watch?v=NJxPiqW5Ww4)
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Showing FY3200 harmonics under magnification
https://www.youtube.com/watch?v=uzUv1s65ziQ (https://www.youtube.com/watch?v=uzUv1s65ziQ)
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Now moving on to sine wave purity/distortion. Attached is an FFT spectrum of a 10 Vpp set point amplitude at 100 kHz. Measured fundamental amplitude is +4.8 dB or 1.75 Vrms or 4.94 Vpp (low by 1.2%). The largest harmonic was the fifth at -51 dB relative to the fundamental. Based on this spectrum I would say THD is < 0.5% although I don't have a direct THD measurement. Easily below the published spec of 0.8% at 1 kHz. See attached scope shot "FY3206S MDO3104 100kHz Sine Spectrum 5Vpp.png". :)
Lastly, I checked the noise and distortion while outputting the smallest amplitude set point of 10 mVpp. The noise on the waveform with the scope set to 1 mV/div was a fuzzy width of the sine waveform of about 0.4 mVp-p or about 0.15 mVrms which is close to the scope's measurement noise. Looking at the spectrum the largest harmonic is about 40 dB down. Note that at this small level there are harmonic lines showing up at 140 kHz which is not related to the 100 kHz sine and is either a generator noise and/a very high frequency signal aliasing on the scope's 100 MS/s setting for this measurement. At any event that spectrum peak is only 30 uV rms. All in all, pretty good low amplitude results. See attached scope shot "FY3206S MDO3104 100kHz Sine Spectrum 5mVpp.png". :-+
Further work on my 331A as well as using a scope of the output to tune in the absolute lowest distortion
Input voltage 5.5VRMS except for 40hz and below (around 3.7VRMS MAX) NO LOAD
I REPEAT NO LOAD MEASUREMENT!!!!
10 .205
20 .195
30 .205
40 .205
50 .195
60 .205
70 .205
80 .205
90 .205
100 .21
200 .21
300 .21
400 .205
500 .21
600 .21
700 .208
800 .208
900 .208
1000 .205
2000 .195
3000 .195
4000 .192
5000 .192
6000 .2
7000 .2
8000 .2
9000 .198
10000 .2
15000 .198
20000 .192
25000 .192
30000 .192
35000 .183
40000 .182
45000 .180
50000 .176
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What happens at 600 Ohm termination with the distortion levels? :popcorn: Can you give some at 50 Ohm as well? It would be nice to see :)
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Before I give the measurements, you can see the weakness of this unit under load.
Consider 1KHZ 0 OHMS @ 5.5VRMS = .205
@50 OHMS :
1V RMS = .175 %
2V RMS = .900 %
3V RMS = 8.800 % (clearly visible rounded peaks on the oscilloscope)
I settled on 1V RMS to do the testing.
1V RMS
0 OHMS 50 OHMS
50 .190 .215
100 .165 .172
500 .180 .180
1000 .170 .175
5000 .164 .165
10000 .162 .175
30000 .156 .167
50000 .140 .155
100000 .142 .155
200000 .130 .135
300000 .110 .125
600000 .095 .110 (MAXIMUM INPUT FREQUENCY)
Also, a video of the process
https://www.youtube.com/watch?v=455QlMK2NUk (https://www.youtube.com/watch?v=455QlMK2NUk)
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Does anyone know how to change the input power to 230V? I got mine with a US plug, so it's probably set to 110V.
The inside seems to have a 4-pin power selector (labelled as CN1 and CN2), but without instructions I don't know which combination to use.
Edit: It does seem to work for both 110V and 230V. I removed the circuit board and the power selector only had 1 viable option. So I fired it up and luckaly it didn't explode in my face.
But now I seem to have another issue. When I connect it to my scope, the output voltage (when it's off!) is almost 300V! At 50Hz. It's probably floating, but does anyone has a tip to ground it? Until than I can't use it for anything without frying my circuits. |O
Edit2: I fixed it. See my other post. https://www.eevblog.com/forum/beginners/function-generator-output-floating-300v!/ (https://www.eevblog.com/forum/beginners/function-generator-output-floating-300v!/)
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I recently received my FY3224S and I installed the driver and software on my W7 64bit machine. Everything appears to work but the interface is in Chinese. How do I go about changing this to English? I tried downloading the earlier versions of the software in this thread but the same thing happens.
Any help would be appreciated.
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I recently received my FY3224S and I installed the driver and software on my W7 64bit machine. Everything appears to work but the interface is in Chinese. How do I go about changing this to English? I tried downloading the earlier versions of the software in this thread but the same thing happens.
Any help would be appreciated.
The link fc12 posted has the English version of the software. Only the earlier version (v1.4 IIRC) is in English. The latest version is Chinese only.
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I recently received my FY3224S and I installed the driver and software on my W7 64bit machine. Everything appears to work but the interface is in Chinese. How do I go about changing this to English? I tried downloading the earlier versions of the software in this thread but the same thing happens.
Any help would be appreciated.
The link fc12 posted has the English version of the software. Only the earlier version (v1.4 IIRC) is in English. The latest version is Chinese only.
Thanks for help.
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I'm thinking of buying a FT3224S for a project - does anyone know the frequency accuracy in ppm or whether the input can be driven from a 10MHz reference standard to improve overall accuracy?
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Hi,
I also got one. Feeltech FY2200S (10MHz)
but i have a problem with the offset voltage. See measurements below. Can someone please check if they have the same offset issue?
Set Measured
0.0 0.001
0.1 0.209
0.2 0.314
-0.1 0.045 (positive? must be negative)
-0.2 -0.059
By the way, the signals are made with 8 datalines from a FPGA (altera max II) these digital lines are fed to a R2R network..
There are some adjustment potmeters inside. found the ofset one and the anplitude one. but there is one more..
Thanks,
peter.
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I'm thinking of buying a FT3224S for a project - does anyone know the frequency accuracy in ppm or whether the input can be driven from a 10MHz reference standard to improve overall accuracy?
There's no external reference input. I don't remember the specs offhand, but I'd say that if accuracy is important then you're best off with a proper function generator. This fills a niche when you don't want to do without and can't justify the cost of something better, but don't mistake it for something more than that.
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I'm thinking of buying a FT3224S for a project - does anyone know the frequency accuracy in ppm or whether the input can be driven from a 10MHz reference standard to improve overall accuracy?
Perhaps you can hack it and change the crystal/oscillator with a more stable one. The generators are certainly cheap enough to take a chance.
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I'm thinking of buying a FT3224S for a project - does anyone know the frequency accuracy in ppm or whether the input can be driven from a 10MHz reference standard to improve overall accuracy?
Perhaps you can hack it and change the crystal/oscillator with a more stable one. The generators are certainly cheap enough to take a chance.
Plenty of room in them, too.
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I am basically a Linux user and I don't like to buy hardware that can't work with Linux. But I really need a waveform generator and the price on this one is attractive. Does the included software run under Wine?
What functionality does the software add?
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There's no external reference input.
Thanks for the clarification. I didn't expect great accuracy so if it accepted a reference then it would have worked for my current project.
Perhaps you can hack it and change the crystal/oscillator with a more stable one. The generators are certainly cheap enough to take a chance.
That is a good thought and I like the spirit however if it isn't successful then it is £60 I won't have to put towards a better function generator. It's a tough decision, I'm going to think it over a bit more.
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I am basically a Linux user and I don't like to buy hardware that can't work with Linux. But I really need a waveform generator and the price on this one is attractive. Does the included software run under Wine?
What functionality does the software add?
It uses a USB to serial converter which Linux picks up just fine. The protocol is documented somewhere earlier in this thread. I started hacking up a Python lib for it, and got most of the way there but didn't get around to finishing it off because I've not needed it in a while. It would be pretty easy to hack up a GUI for Linux but I don't think one exists yet.
The included software is kinda shitty so I never bothered trying it.
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I was surprised at how accurate the frequency my 24MHz Feeltech unit was. All my frequency counters have it dead accurate.
A piece of Tek or HP piece of test gear it is not, but the thing is very effective, and quite accurate, especially for the price.
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That's good to know. And even if was slightly off then still really good value for money. I've decided to save up a bit longer and find something more fitting to my current needs - I suspect I'll defect to the SDG2042X camp, but will end up with a feeltech in the travel bag eventually.
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So there is a lot of free space in this waveform generator, has anyone attempted a battery conversion yet?
The front board is supplied with a handful of voltages, so would need to generate those from a battery, but seems like it should be doable.
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Hi guys,
I am having a problem with this device. I have installed the driver and software on my W7 64bit machine, but when I connect the fy3224s to the laptop, the program FY3200 PC control software does not recognice the device.
How many programs have i to install on the laptop? The Ch340driver,...it is necessary to install on the laptop?
(http://i1346.photobucket.com/albums/p699/ferdiii1/IMG_20160116_200024_zpsbfm9u6cr.jpg) (http://s1346.photobucket.com/user/ferdiii1/media/IMG_20160116_200024_zpsbfm9u6cr.jpg.html)
Any help would be appreciated.
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Not being a windows guy I don't know what you need to see there but you should look at the device manager to see if whatever (USB to serial, maybe) device they use is listed there. If it isn't maybe you need to install its driver, whatever it is?
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Hi guys,
I am having a problem with this device. I have installed the driver and software on my W7 64bit machine, but when I connect the fy3224s to the laptop, the program FY3200 PC control software does not recognice the device.
How many programs have i to install on the laptop? The Ch340driver,...it is necessary to install on the laptop?
(http://i1346.photobucket.com/albums/p699/ferdiii1/IMG_20160116_200024_zpsbfm9u6cr.jpg) (http://s1346.photobucket.com/user/ferdiii1/media/IMG_20160116_200024_zpsbfm9u6cr.jpg.html)
Any help would be appreciated.
The way to have described the problem implies that you have two computers you are trying to use the FY3224S device with: a W7 64bit machine and a separate laptop. Your last sentence "The Ch340driver,...it is necessary to install on the laptop?" gives me the impression that you have not installed the required driver on the laptop, only the W7 64bit machine.
Follow the manufacturer's instructions, disconnect the FY3224S, install the supplied (required) USB driver on the laptop and then connect the FY3224S. Worked seamlessly for me.
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Is the software any good? The screen looks decent enough.
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"good" is a subjective term. I would say it is superior to the Chinese version of some software that many FY3200S users initially received, but in reality it is far from complete. It is more like alpha software thrown together for a targeted user base to provide feedback to its developers.
I have been experimenting directly with the device sending commands via a terminal program in order to better understand how to control the device and what can and cannot be done via the front panel and the USB interface. I am using information gleaned from this post and several other sources. I am discovering all sorts of interesting behaviors. For example:
1) Is is not possible to set the phase angle of the CH1 waveform via the USB interface, but it can be done set though the UBS interface.
2) The internal counter rolls over at 268,435,456 (2**28-1).
3) ... the list goes on.
Right now I am trying to understand the trigger options. I am stumbling around trying to understand what these options do and how to to use them. I would appreciate if someone could provide some clarity. What is the relationship between the counter and the triggering options?
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Well, I finally got a better understanding of what triggers do on the FY3224S. There is no relationship to the counter even though all the trigger settings are accessed under the [Count] button on the front panel.
Setting a Trigger
A trigger is used to initiate a pulse of the CH1/MF waveform, n number of times, as defined by the CP_CNT (CyclePlus_Count) value. There are three triggering modes: manual (Manual Trigger), external (Ext Trigger), or channel CH2/SF frequency (CH2 Trigger). Here are the pertinent command that control triggering...
tt0 Trigger manually. A trigger event is initiated by physically depressing the [ADJ] knob on the front panel.
Note: A “manual” trigger event cannot be initiated programmatically.
tt1 Use the signal from the BNC connector labeled Input on the front panel for the trigger.
tt2 Use CH2/SF frequency as the trigger.
tnn Set number of waveform cycles to output (CP_CNT value), where n is the number of cycles.
Note: Changing the CP_CNT value programmatically causes the trigger mode to change to manual trigger mode.
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Indeed, I think they just clogged it under the counter option to save another button and perhaps the fact that in trigger mode, you can set the number of cycles (Count) that will be out put on a trigger event. For example set the main frequency to 1 kHz and trigger on say 50 hz (either from an external or channel 2 source) and CP_CNT to 10, you will get 10 waveforms of 1 usec each repeating every 20 msec.
I'm still looking for a problem to solve with this feature :-/O
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I bought the FY3220S. It is V1.2 and I have applied the trick to get it to 24MHz which worked, on power up it reports that it is an FY3224S.
The problem I have (which existed before changing the max freq) is the output at low frequencies. Below 100Hz the square wave deteriorates badly and becomes unusable. Please see the attached images at 100Hz, 10Hz, 1Hz and 0.1Hz
Is there a firmware update that will fix this? Or any fix for that matter?
thanks
Ted
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Turn off the AC coupling on your scope!
Neat the frequency hack worked on yours though. You are lucky...
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Duh - thanks
Yes, it is great that the fix worked :)
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I bought the FY3200S 24MHz a few days ago. To my use it works, but it seems to have some issues.
I haven't tested much, but here is one problem I have found so far.
In what I would call BURST mode where CH1 is triggered by CH2 to give CP_CNT pulses, it will give an extra spike about half the peak value of the real pulses. A count of zero will give only the spike. I have attached a print from a SIGILENT SDS 1052DL.
The spike i about 20ns long and comes where the next pulse should have started. This is an annoying thing when testing burst input to a microprosessor. On the scope it shows up only now and then with 500MSa/s, but my 100MHz analog scope shows it very well.
skarven
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These are all new function generators so they really should fix glitches, maybe with new firmware.
That will be the test whether they are in it for the long haul, or are a fly by night operation.
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Hi guys, does anyone know the opamp used in this generator? I mean the ones in the output stage. I need to know the maximum current output of CH1/2.
Thanks!
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Output stage uses THS3002I (if you search for the datasheet, search for THS3001).
Here is an overview:
High Speed
– 420 MHz Bandwidth (G = 1, –3 dB)
– 6500 V/µs Slew Rate
– 40-ns Settling Time (0.1%)
High Output Drive, IO = 100 mA
Excellent Video Performance
– 115 MHz Bandwidth (0.1 dB, G = 2)
– 0.01% Differential Gain
– 0.02° Differential Phase
Low 3-mV (max) Input Offset Voltage
Very Low Distortion
– THD = –96 dBc at f = 1 MHz
– THD = –80 dBc at f = 10 MHz
Wide Range of Power Supplies
– VCC = ±4.5 V to ±16 V
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Output stage uses THS3002I (if you search for the datasheet, search for THS3001).
Thank you very much! So THS3002I is the dual version of THS3001 right? And I think that each channel uses two opamp in parallel like in the 5200A, isn't it?
From the specs (much better than AD812) it seems there is no need to replace it!
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I'm not 100% sure but IIRC they use only one stage for the output. The other maybe for feedback.
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Just received it! But why the hell it's still using 9600bps in 2016!! The waveform uploading is really slow :(
Unfortunately the only way to fix this issue is to edit the firmware :/
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If you're using their supplied software, its even worse as there are quite some pauses built in to their protocol. With the LabView interface I've created I can upload a waveform in about half the time. Of course, if they used higher baudrates this would be even less of an issue.
More annoyingly IMHO is the fact that sending commands over the interface disturbs the waveforms (e.g. setting a new frequency causes a slight interruption in the signal) :-//
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I found the unbranded FY3224S Function generator on the Banggood.com site.
I have purchased many things there,no problems at all, and shipping time is very good
Right now this unit is selling at $69.99 with free air or direct shipping to the US.
It appears to include a software disc, USB cable,2x coax cables with alligator clips and power cord.
http://prntscr.com/acvpn4 (http://prntscr.com/acvpn4)
Here's a link the product:
http://www.banggood.com/FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1014034.html
(http://www.banggood.com/FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1014034.html)
I believe I am going to order one soon as i only have a 2Mhz FG and an RF generator.
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I was just using my Feeltech FY3224S and felt something biting me...the culprits turned out to be electrons...I was getting a shock. When I measured AC voltage with a multi-meter from any of the ground points on the Feeltech (e.g. the outside of the BNC connectors) to AC ground, I had around 19vrms.
I opened my unit and the power supply is clearly designed to be isolated. There is no DC continuity between DC ground and AC Hot or Neutral. However, something is wrong because there is a steady 19-20vac between the BNC grounds and AC safety ground. Would someone else please check whether their unit is isolated?
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I connected my scope to ground on the FY3224S (No ground connection). THere is a 100Hz "ripple" with an amlitude of app. 19.5 Volts.
I is quite high-impedance though. A 10k resistor will reduce it to about 1 Volt. This should give a current of about 0.1mA.
I do not know if it "should" be like this, but I think this is rather normal with switch mode power supplies. The oldfashioned transformers are better and produce less noise too!
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Hi SKarven, thank you for checking and for the quick response!
Connecting my scope to any BNC connector ground on the FY3224s (no ground connection from the scope) shows a switching pattern (not a sine wave) at 60Hz that is 82volts peak-to-peak and ~20vrms; that's why I could feel it. Fortunately, as you pointed out, the current is low (less than 1mA) so it does not appear to be a major safety hazard...at least not for humans.
However, I'm much less confident that 82vpp AC will be healthy for many of the circuits I connect to the signal generator. I've sent an inquiry to Feeltech; it will be interesting to see what they say. In the meanwhile, I won't be connecting anything to my FY3224s.
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Here is how the signal looks on my generator. I have a 50Hz 230V mains.
And I agree, too high voltage for many applications. One solution would be to ground the thing to AC ground and let that handle the current, but this will of course create problems with ground loops... The only good solution would be a isolation transformer on the mains, but this will add so much to the cost that it might be better to buy another Signal Generator.
It would be very interesting if someone with a different Signal Generator could make the same measurements.
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I have the same effect with my FY3200. It is caused by the mains filter in the switched mode power supply. An isolation transformer isn't going to help here. An option would be to disconnect the mains filter towards the ground of the generator or (better) mount a grounded power inlet.
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NCTNico: I suspect you are right. My PS board is heavily hot-glued to the chassis, but there is an EMI filter with two Y-caps. I'm going to try to dig out the power supply board from the hot glue and see what the story is. I wonder if I'll find some safety caps connected from AC mains to DC ground instead of earth ground.
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From the photos I think the large blue capacitors are the ones connected to ground. It will be much easier though to put a grounded IEC inlet in the case.
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Those are the Y-rated safety caps. There is a third that bridges the HV and LV sides of the transformer. I'd rather not connect the DC outputs to earth ground because that can introduce other problems; the DC ground should float. Worst case, perhaps I'll replace their PS with a linear supply which should be quieter anyway...and safer. It looks like the supply is +/- 12v, +5v, +3v3.
However, at this point, I'm curious and would like to figure out what is wrong with their design. Unfortunately, they used a *lot* of hot glue to secure the PS board and it's really hard to get out; I'll need to revisit this when I have a bit more time.
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Those are the Y-rated safety caps. There is a third that bridges the HV and LV sides of the transformer. I'd rather not connect the DC outputs to earth ground because that can introduce other problems; the DC ground should float.
This generator isn't designed to have the DC ground floating. For EMC and safety reasons it is better to ground the outputs.
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I was thinking about replacing the psu with a linear one too. For my current project I am more worried about ground loops and related issues rather than (human) safety. I will connect the siggen to a custom pcb which, in turn, it's connected through two usb ports to a desktop computer. This pcb is powered by a linear psu where the ground can be lifted from earth, but the two usb connectors are earthed through the PC psu. At some point I will also probe the signal on the board with my oscilloscope, so another ground->earth connection will be established. Of course my pcb will connect all grounds together.
Should I ground lift the oscilloscope in order to have a single earth connection?
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I just ordered one of these, can't wait to get my hands on it.
I wonder what would happen if a bigger company designed a function generator around the $100 price point. Seems to me that there is room for improvement. I'd pay an extra 30 dollars for better grounding, better phase control and a faster baud rate.
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I agree: the power supply used in this generator was designed to be earth grounded. I would be very surprised if this passed FCC or CE EMC compliance testing and there are likely safety issues too. I think the two choices with this signal generator are to replace the power supply (+12, -12, +5, +3.3) with one that properly isolates the DC outputs or replace the two-conductor power connector with a three-conductor connector and earth reference the DC ground. Thanks again!
MODERATOR: This issue should probably be something flagged at the top of this topic; please consider it.
Those are the Y-rated safety caps. There is a third that bridges the HV and LV sides of the transformer. I'd rather not connect the DC outputs to earth ground because that can introduce other problems; the DC ground should float.
This generator isn't designed to have the DC ground floating. For EMC and safety reasons it is better to ground the outputs.
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So I just did some tests and the generator works fine down to 27v DC applied directly to the AC input. I think I will go ahead and make it fully battery operated with a few lithium ions and a boost converter.
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Just got myself one of these and had a quick look around inside it. On a look over the board, I see that there's a buffer op-amp just before the final (under the heatsink) output driver, which is a 4558D. I looked up the specs of that - a terrible 3MHz unity gain bandwidth and 1.7V/µs slew rate. That may go some way to explaining why this thing doesn't work so well up beyond a few MHz.
I'll have a more careful trace of it in a few days time and see if I can work out enough of the circuit diagram around it to post here with a suggestion of what it's doing in the signal path, and some scope traces before and after it. I might then see if I can have a go replacing that chip with something a bit faster and see if it improves matters.
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Just got myself one of these and had a quick look around inside it. On a look over the board, I see that there's a buffer op-amp just before the final (under the heatsink) output driver, which is a 4558D. I looked up the specs of that - a terrible 3MHz unity gain bandwidth and 1.7V/µs slew rate. That may go some way to explaining why this thing doesn't work so well up beyond a few MHz.
I'll have a more careful trace of it in a few days time and see if I can work out enough of the circuit diagram around it to post here with a suggestion of what it's doing in the signal path, and some scope traces before and after it. I might then see if I can have a go replacing that chip with something a bit faster and see if it improves matters.
Would it be possible to put an oscilloscope probe on the input of that buffering op amp?
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Would it be possible to put an oscilloscope probe on the input of that buffering op amp?
Absolutely, yes. I'm planning quite an indepth review/look over various bits of it, just as soon as I've rebuilt my workshop again. It's currently quite literally in pieces while I upgrade the mains power supply arrangements, so all my equipment is sitting around on the floor in piles of boxes.
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I just received my FY3324S that I ordered off of banggood. It did come branded as "FeelTech", even though the pictures do not show that branding.
Please help me understand the grounding situation.
-The front panel clearly has ground symbols with lines pointing to the BNC connectors
-The BNC connectors all share the same reference (I verified this with a meter)
-The BNC reference is NOT the mains earth ground or neutral
-The BNC reference is not completely floating
-The BNC reference is somewhere around 20VRMS above earth ground (based on people's reports)
So what happens when I connect this function generator to a grounded circuit?
-Would the voltage difference between the BNC reference and a real ground cause a measurable current?
-Would the function generator go from "kind of floating" to "grounded"?
-If there is a difference in ground reference between a circuit and the function generator, could this cause equipment damage?
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I just did a quick test on the 4558D. It seems to be used only for the DC offset. I see no signal on any pin.
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Sigh. I'm almost sorry I found this thread. I was looking at building the FG from AoE3 (www.artofelectronics.com/synthesizer (http://www.artofelectronics.com/synthesizer)) as my next project. I had already figured to cost reduce it by replacing the two AD9954's ( 2 @ $34.40) with an FPGA (XC3S50A $8.05). I've even gone so far as to write and simulate a good chunk of the FPGA code.
Then you folks show me that FeelTech has already implemented it and is selling it for seventy-five bucks. Even DIY I could not beat that price.
Of course, if I just buy the FeelTech I don't get the "experience" of creating it myself. Or the headaches either. Some features might be different. I'm more interested in FSK/PSK modulation than with arbitrary waveforms, though there's no reason AWs can't be done. The timing analysis of my FPGA design says that it should be able to do 200 Msps so that is about the same. I had not even started to design the UI yet and only just started simulating the filters in LTSpice.
Another difference would be that I would OSHW the whole thing. I'd likely have to lean on you folks some to smooth the kinks out of the analog circuitry since I'm stronger in digital. What might make it worthwhile would be to turn it into a community project and get more folks to contribute feature and design ideas. More eyes on the design would likely improve utility and stability.
So what do you think? Start a significant community project (would anyone really contribute?) or just buy a FeelTech and be done with it? :-\
Thanks,
- Chip
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Buy the FeelTech. Take it apart and identify the weaknesses in the design. Come up with DIY solutions to improve the design of the FeelTech. Or you could also pass the improvements on to the engineers of FeelTech, so that they come up with an improved version. This way you learned a lot about it, and at the same time helped the other existing FeelTech users. Win win :)
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https://www.youtube.com/watch?v=BqxA4HRYjVg&feature=youtu.be (https://www.youtube.com/watch?v=BqxA4HRYjVg&feature=youtu.be)
Not sure how to turn this into an embedded video.
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https://www.youtube.com/watch?v=BqxA4HRYjVg&feature=youtu.be (https://www.youtube.com/watch?v=BqxA4HRYjVg&feature=youtu.be)
Wow! Comments seem to be disabled on YouTube, which is a shame. Nice video, though. Now I am going to have to have a look at mine.
I wonder if that is just ghost voltage, or what. A 20,000 ohm per volt analog meter should let you easily tell the difference.
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Review of FY3224S. There is a coupon code to get $4.44 off the price.
https://www.youtube.com/watch?v=07BOm0UKJk4 (https://www.youtube.com/watch?v=07BOm0UKJk4)
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I found a similar 165V peak to peak waveform on my BNC outside contacts. Indeed the polarity of the outlet did make a difference. Reading it with analog meter seems to indicate it is a ghost voltage, without much current. I was using a 20,000 opv Simpson. You probably need a 1000opv.
So do these guys need to be tied to ground?
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I've been working on creating a drawing of the power supply board.
I looked up the datasheet of the smps chip, and noticed something odd. The "typical application" has a cap connecting the smoothed DC output of the bridge rectifier to the output ground reference.
Am I correct in thinking that is a mistake, and that they probably meant to couple the two ground references together?
edit: I also don't understand C1, depending on the capacitance value wouldn't that effectively just be a short circuit?
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C10 is not a mistake. It is a common way to reduce emissions. It also causes the leakage from mains to the generator's outputs.
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C1 L1 form a low pass filter, to reduce noise from the power supply, from both the switching transistor and the incoming bridge rectifier diodes, from being passed back to the power supply and radiated out to other mains devices. Added to pass EMC compliance, as otherwise a SMPS can be a very broadband RF noise source.
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Just got this similar Feel Tech FY2200S delivered a half hour ago. In process of figuring out all it's capabilities.
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The FY2200 PC software installed OK on a Win7 x64 laptop but I found a bug. When selecting triangle wave on Channel 1 it actually outputs a square wave. And of course that makes square selection reversed too. Channel 2 is correct.
D'OH!!! |O
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The FY2200 PC software installed OK on a Win7 x64 laptop but I found a bug. When selecting triangle wave on Channel 1 it actually outputs a square wave. And of course that makes square selection reversed too. Channel 2 is correct.
D'OH!!! |O
When I try to install the software I get a Launcher Error - "Unable to open archive file" message. Any ideas?
Also - is the UI still all in Chinese? Perhaps it would be worthwhile to develop a browser UI since much of the serial protocol has been uncovered.
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Is that 115v on the bnc something to be concerned about? I cannot figure out why rotating a plug makes any difference to an ac input (mains).
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The FY2200 PC software installed OK on a Win7 x64 laptop but I found a bug. When selecting triangle wave on Channel 1 it actually outputs a square wave. And of course that makes square selection reversed too. Channel 2 is correct.
D'OH!!! |O
When I try to install the software I get a Launcher Error - "Unable to open archive file" message. Any ideas?
Also - is the UI still all in Chinese? Perhaps it would be worthwhile to develop a browser UI since much of the serial protocol has been uncovered.
No idea why you get that error message. The GUI in my copy is in English. I upgraded my laptop today to Win10 and it still works fine other than that dumb bug on Channel 1. Haven't found any other bugs yet.
If you want a copy send me a PM. It's 6.5 MB. But I'll have to change the extension on the file to something else or put in a zip file because Gmail doesn't allow you to send files with an .exe extension.
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Is that 115v on the bnc something to be concerned about? I cannot figure out why rotating a plug makes any difference to an ac input (mains).
If you're talking U.S. mains one side is hot (115V - 120V) and the other side is neutral (tied to ground at the breaker box). The outlets have one slot larger than the other to accept a "polarized" 2 prong plug that insures hot to hot and neutral to neutral. However, the line cord on these units have both prongs the same size (small) which allow it to be plugged either way. Therefore, if that noise capacitor is now connected to the "hot" side it allows a leakage current to the internals.
I wonder if it would trip a GFCI protected circuit?
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I wonder if it would trip a GFCI protected circuit?
It has never tripped my GFCI, which it is plugged into.
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I wonder if it would trip a GFCI protected circuit?
It has never tripped my GFCI, which it is plugged into.
I think for safety's sake I'm going to install a polarized plug to insure that cap is always on the neutral side.
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Looking on Ebay with FY3224S as the search term I can see many signal generators with different specifications. Bandwidth appears to be either 2 MHz, 5 MHz, 6 MHz, 8 MHz, 10 MHz, 12 MHz, 20 MHz or 24 MHz. Please could someone explain?
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There are different versions with different capabilities, for different prices. Sometimes you can hack the lower spec model into the higher spec, but this is not guaranteed. Unless you are really trying to save a few dollars just get the 24MHz model and be done with it.
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There are different versions with different capabilities, for different prices. Sometimes you can hack the lower spec model into the higher spec, but this is not guaranteed. Unless you are really trying to save a few dollars just get the 24MHz model and be done with it.
I agree with this, but I'd like to add that the 32xx series has arbitrary wave form generation while the 22xx series does not.
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I wonder if it would trip a GFCI protected circuit?
It has never tripped my GFCI, which it is plugged into.
I think for safety's sake I'm going to install a polarized plug to insure that cap is always on the neutral side.
First of all those capacitors are designed to be safe so no problems there. Secondly depending on a polarised plug to have the neutral where you expect it for safety is a bad idea. There are soooo many things which can go wrong with wiring! For example: what happens if the neutral gets interrupted somewhere? There is only one way out: ground the power supply!
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I wonder if it would trip a GFCI protected circuit?
It has never tripped my GFCI, which it is plugged into.
I think for safety's sake I'm going to install a polarized plug to insure that cap is always on the neutral side.
First of all those capacitors are designed to be safe so no problems there. Secondly depending on a polarised plug to have the neutral where you expect it for safety is a bad idea. There are soooo many things which can go wrong with wiring! For example: what happens if the neutral gets interrupted somewhere? There is only one way out: ground the power supply!
Yes the Y-Rated cap would be safe for connecting line to ground. The problem is that it isn't connected to ground, and therefor not currently safe (as seen by 115VRms on the floating ground).
The other issue I have is that if the non-polarized plug is flipped the wrong way the fuse is on neutral. This is not acceptable to me, if the fuse blows the power supply needs to be disconnected from line and not from neutral.
I agree with you regarding the grounding, I'd like to get this sucker on a proper 3 prong plug and grounded.
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There is not enough current flowing through the capacitors to cause harm to your body.
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First of all those capacitors are designed to be safe so no problems there.
You really want to put your safety to a Chinese capacitor? Chances are nothing will go wrong but Mr Murphy is always lurking around the corner.
Secondly depending on a polarised plug to have the neutral where you expect it for safety is a bad idea. There are soooo many things which can go wrong with wiring! For example: what happens if the neutral gets interrupted somewhere? There is only one way out: ground the power supply!
If the neutral opens up and nothing is connected to the BNC's the unit won't power up. And I'm not even sure it will power up even if it's connected to a grounded device. Granted, a 3 wire grounded plug is the BEST solution. Next best is a polarized 2 prong plug as long as the fuse is on the hot side. That needs to be checked out.
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The neutral doesn't open in the device ofcourse :palm: Imagine this happening in your breaker box! In that case neutral will become live and this isn't a rare event!
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The neutral doesn't open in the device ofcourse :palm: Imagine this happening in your breaker box! In that case neutral will become live and this isn't a rare event!
I wasn't inferring that the neutral opens in the device. There are all kinds of scenarios that could take place with mains wiring and we could debate that ad nauseam. In 2 cases that I am personally familiar with a neutral open resulted in dead outlets. I had another case where I discovered by chance that the outlets were wired backwards and had been for years and nobody knew it. Ain't THAT a scary thought!
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Dead sockets yes but harmless: definitely not!
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I pulled the 3 prong plug out of an old Dell ATX power supply, and it's perfect. It happens to have the same exact white connector on it, even in the right polarity, with a separate ground wire.
Time to run to harbor freight to pick up a dremel tool
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Took some measurements today and got interesting results. See photos. Initially no matter which way I plugged the line cord I got 1.2 mv AC. Then I realized that the USB cable was plugged into my hub. Unplugged it and BINGO! :scared:
Fluke 87 connected between the outside barrel of the BNC and electrical (earth) ground.
Power on, 56.9 VAC
Power off, 1.357 VAC
Then I reversed the line cord. Power off, 107.1 VAC
Power on, 59.7 VAC
I tried taking some current measurements and got nothing because the leakage voltage dropped to zero.
Next step is to open this bad boy up and see if there's a safe way to insure it's grounded. It does not appear that a 2 prong polarized plug is a complete solution.
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Greetings all, I decided to pull the heatsink from the output amps on the FY3200S front panel board. The parts appear to be TI parts, but I have not been able to find the datasheet anywhere on Google. I also tried the TI database as well. I can't figure this out, I was hoping someone might be able to come up with a part number/datasheet so a good schematic of the signal chain can be made. Of course I could guess and write down what I think is there, but I would rather be certain. See photo of the output stage amp below.
Almost forgot, here is a link for the TI part number lookup database that I tried.
http://www.ti.com/packaging/docs/partlookup.tsp#divline (http://www.ti.com/packaging/docs/partlookup.tsp#divline)
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It's a THS3002.
http://pdf.datasheetcatalog.com/datasheets/700/322243_DS.pdf (http://pdf.datasheetcatalog.com/datasheets/700/322243_DS.pdf)
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I opened it up today.....
3 wire cord installed and grounding verified.....
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It's a THS3002.
http://pdf.datasheetcatalog.com/datasheets/700/322243_DS.pdf (http://pdf.datasheetcatalog.com/datasheets/700/322243_DS.pdf)
Excellent work.
I see its headline stats are:
420MHz GBW product
6500V/µs slew rate
At a GBWP of 420MHz, I'd expect to see no more than 17.5 times gain around it if it's going to achieve 24MHz output.
A slew rate of 6500V/µs would allow a worst-case rise time of -10V to 10V in 3ns leading to a near-straightline triangle wave output at any period faster than 6ns, equating to 166MHz. We should therefore expect this amp to handle a nice-looking square wave at anywhere below about a tenth of that; 16MHz. Sounds to me, at least on these paper specs alone, that this chip is more than adequate to handle the quoted specs of the generator; at 24MHz sine and 6MHz square/triangle. Yet it's observed in practice that this machine just can't cope with this limit.
Do we have an idea of the surrounding circuit connectivity around it? How easily can it be traced without taking the heatsink off? I'm loathe to do that to mind just yet but if someone else has already done it could they trace out the periphery of this chip? I'd be interested to see what the gain is set to on this amp.
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I see its headline stats are:
420MHz GBW product
6500V/µs slew rate
A slew rate of 6500V/µs would allow a worst-case rise time of -10V to 10V in 3ns leading to a near-straightline triangle wave output at any period faster than 6ns, equating to 166MHz.
Oh except literally as a post that I see the next headline stat of
40ns settle time to 0.1%
So even if it can slew -10 to 10V in a supposed 3ns, it'll be 40ns before it settles. A maximum square period of 80ns, coming out at 12.5MHz at absolute best. I think maybe it's that settle time that causes it not to cope so well at sharp edges.
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I notice that the manual is lacking pictures of any of the waveforms. So I captured them.
Here's some screenshots from my Rigol DS1054Z watching the output of the main channel (CH1) when set to 10kHz 1V pk.
SINE = Sine; SQUR = Square; TRNG = Triangle.
PRE1 = Lorentz; PRE2 = Multitone; PRE3 = Random noise
PRE4 = E.C.G.; PRE5 = Trapezoidal; PRE6 = Sinc
PRE7 = Narrow pulses; PRE8 = White Gaussian noise
PRE9 = "amplitude modulated"; PRE10 = "frequency modulated".
No point capturing the ARBs because those are user-uploaded anyway (and also they're all blanked to zeroes in my unit anyway :) )
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I doubt that it's a THS3002. Even if there is a datasheet, where the THS3002 is labeled "PRODUCT PREVIEW", I cannot find it at ti.com
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I just modded my FY3224S with a proper 3-wire grounded power cord... and managed to blow up the power supply board, (in spectacular fashion I might add), in the process of making this thing "safer". :palm: I won't go too deep into my faux-pas, but suffice it to say that you are supposed to connect the SECONDARY-side-gound (low voltage DC ground) to mains-earth-ground. Do NOT, under any circumstances, connect the PRIMARY-side "ground" (from the bridge rectifier) to mains-earth-ground. That isn't a meant to be earth-ground. It's the ground "reference" of the primary.
I've noticed that FeelTech is using whatever power supply they can get their hands on, as mine looked nothing like the ones posted by med6753 & tombddiver. My unit came with a very nice SICO-650 power supply. (Well, it WAS nice 'till I fried it). I put in a "Universal DVD Replacement Power Supply" I managed to find on Amazon. It took some searching to find one with the required +5v & +/-12v outputs.
My mod included a toggle switch in the grounding path, in case I ever have the need to "float" the BNC outputs, the way the unit is shipped from FeelTech. Otherwise that switch stays in the safe/gounded position.
One more note; The sticker on the bottom of the unit is printed on an ink-jet printer. If it gets wet, it will bleed and smear.
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Speaking for alternate power supplies...
Does anyone have an idea of what the power requirements are for this unit?
I have this ready-made transformer board that produces (unregulated) +/15 and +5 - at least that's what the silk screening says.
The specs on the transformers read:
- 2 x 10.0 V, 2 x 5.0 VA
- 2 x 8.0 V, 2 x 1.25 VA
Do you think it will work if I just use some 78xx and 79xx regulators?
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Speaking for alternate power supplies...
Does anyone have an idea of what the power requirements are for this unit?
I have this ready-made transformer board that produces (unregulated) +/15 and +5 - at least that's what the silk screening says.
The specs on the transformers read:
- 2 x 10.0 V, 2 x 5.0 VA
- 2 x 8.0 V, 2 x 1.25 VA
Do you think it will work if I just use some 78xx and 79xx regulators?
I doubt it's more than a few hundred ma and 78xx and 79xx regulators would work no sweat. There's plenty of room in the case to install a linear supply. I had initially considered doing the same thing if grounding the DC side didn't work out.
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Has anybody in this thread contacted FeelTech about this voltage issue?
Maybe the OP that reported this voltage issue can take the initiative, as he has all the information and measurements at hand.
http://www.made-in-china.com/showroom/hnregong/product-detailFvAJyhUdhnYp/China-Fy2200s-Dual-Channel-Dds-Function-Signal-Generator.html (http://www.made-in-china.com/showroom/hnregong/product-detailFvAJyhUdhnYp/China-Fy2200s-Dual-Channel-Dds-Function-Signal-Generator.html)
What about the software port of the MHS-5200 to the FeelTech FY3224S?
http://hackaday.com/2015/07/01/hacking-a-100-signal-generator/ (http://hackaday.com/2015/07/01/hacking-a-100-signal-generator/)
It would be really nice to have this software available for the FY3224S as it is apparently compatible with the arbitrary waveform format of the easy to use Waveform Manager Plus software!
http://tti1.co.uk/downloads/waveman-plus.htm (http://tti1.co.uk/downloads/waveman-plus.htm)
Conclusion: The moment FeelTech has corrected this potential safety issue in the power supply,
and the moment the software port is completed, you can get a very cheap signal generator that can do an impressive job, including an easy way to generate your own waveform formats. This is rock&roll! :)
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In the process of replacing the power supply that I fried, i connected the front panel electronics to a bench power power supply in order to verify I didn't ALSO fry the signal generator section. I verified that it does not draw much from the +12v rails. I didn't note the actual value but as med6753 has noted, it wasn't more than a few hundred milliamps. This intuitively makes sense. 10v DC into 50 ohm load would be 200mA. I might take mine apart again, and carefully measure the current draw on each rail. But it's not much. The replacement power supply was rated at 400ma on the +/- 12v rails, and 800mA on the 5v rail. That's ~13W total output power.
http://www.amazon.com/Universal-Power-Supply-Circuit-Player/dp/B00NQ2OLB8 (http://www.amazon.com/Universal-Power-Supply-Circuit-Player/dp/B00NQ2OLB8)
I did measure the AC power draw with a cheap AC power meter. It draws ~2W with both channels on, but no load. It went up to ~3.1W driving one channel into 50 ohm load with a 10v sine wave. Guessing it would draw ~4W if both channels were loaded at 50 ohms. My meter isn't super accurate or anything, but it let me know that my 13W power supply isn't being brought to its knees by the function generator.
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BTW, studying the pictures of the function generator throughout this thread, Ive noticed two different function generator main-boards with respect to power (and thus two different types of power supplies). If you look at the photos posted by med6753, his power supply board appearently sends a single DC voltage to the main board via a single black & red wire pair. But on my FG main-board (which looks like the one posted by tombdiver) the power supply generates +5 and +/-12v, and sends it to the FG main board via a 5 wire pin header. I'm assuming on med6753's style of FG, the analog and digital power is generated/separated on the main-board. Mine clearly does that on the power supply board.
So beware. They are not all the same. There are at least two different variants.
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Who is going to contact FeelTech about the power issue?
See in the thread above for contact details of the company FeelTech.
I don't have all the details of the power issue at hand, and believe it would be better if the OP of the power issue takes the initiative.
Who is going to port the software program of the MHS-5200 to the FeelTech FY3224S?
Maybe we can collect some money here all together, and buy a FeelTech unit for the software author of the software program. This way he can do it :)
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...
What about the software port of the MHS-5200 to the FeelTech FY3224S?
http://hackaday.com/2015/07/01/hacking-a-100-signal-generator/ (http://hackaday.com/2015/07/01/hacking-a-100-signal-generator/)
It would be really nice to have this software available for the FY3224S as it is apparently compatible with the arbitrary waveform format of the easy to use Waveform Manager Plus software!
http://tti1.co.uk/downloads/waveman-plus.htm (http://tti1.co.uk/downloads/waveman-plus.htm)
...
Well, the github code referenced to in the hackaday article is simply a spreadsheet and some awk/shell scripts, and combined with the information in reply #19 of this thread it should be rather easy to modify to use Feeltech's serial protocol.
The Waveform Manager Plus program apparently is a Windows-only executable.
I think it would be worthwhile to develop a browser-based program to control these function gens. From what I understand, you can perform serial I/O from the major browsers now, so the program should be rather straight forward to write.
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Hi,
I can't find the CD-ROM of this device (FY32000S) and there isn't any page with the driver and software. I found this http://www.feeltech.net (http://www.feeltech.net) but I can't read chinese ::)
Can some one give me a link?
Thanks
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Who is going to contact FeelTech about the power issue?
...
Who is going to port the software program of the MHS-5200 to the FeelTech FY3224S?
At the price point of this FG (mine was $69.99 including shipping on bangood.com), I highly doubt FeelTech is likely to address either issue. No where do they claim the product is safety certified by any US or european safety standards lab. This is surprising honest, as plenty Chinese products are stamped with false or intentionally misleading CE/UL logos when said-equipent would never meet said-safetly-standard if actually tested.
I just don't see a motivation to compete in the "sub-$100, safety certified, function generator market". This stuff is targeted towards one-man shops in the Pac-Rim countries, and hobbyists in the US and Europe. Real electronics laboratories will buy real Siglent, Rigol, Agilent, BK-Precision, branded, safety certified FGs, and pay well over $400 for them.
I'm not trying to discourage anyone from raising up the issue to the manufacturer, but speaking for me... I stand a better chance of being shocked that FeelTech responded to our INVESTIGATION of ghost voltage on the BNC connectors, than being LITTERALLY shocked by an ACTUAL FAULT in the function generator power supply AC coupling caps.
Just for fun I might go test some other stuff I have in my house with two-conductor power cords looking for AC ghost voltages... I wonder what my Blu-Ray player does...
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A Sony DVD player showed 53v on the ground side of the RCA jacks (and the metal chassis) relative to earth ground measured with my Brymen-257 multimeter on the standard AC setting. This voltage is independent of the DVD player being On or Off. However, when using the LowZ setting on my multimeter the voltage drops to ~1V. The FY3224S measures the same.
I'm not convinced this ghost voltage is even a safety issue, rather a natural side affect of how switching power supplies are designed… Still… I FEEL better leaving the switch I installed in the setting that connects the FG's DC ground to mains-earth ground. I'll leave it in that position unless I have a reason not to.
Cheers.
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I just modded my FY3224S with a proper 3-wire grounded power cord... and managed to blow up the power supply board, (in spectacular fashion I might add), in the process of making this thing "safer". :palm: I won't go too deep into my faux-pas, but suffice it to say that you are supposed to connect the SECONDARY-side-gound (low voltage gound) to mains-earth-ground. Do NOT, under any circumstances, connect the PRIMARY-side "ground" of the switching power supply to mains-earth-ground. That isn't a meant to be earth-ground. It's the ground "reference" of the primary.
I've noticed that FeelTech is using whatever power supply they can get their hands on, as mine looked nothing like the ones posted by med6753 & tombddiver. My unit came with a very nice SICO-650 power supply. (Well, it WAS nice 'till I fried it). I put in a "Universal DVD Replacement Power Supply" I managed to find on Amazon. It took some searching to find one with the required +5v & +/-12v outputs.
My mod included a toggle switch in the grounding path, in case I ever have the need to "float" the BNC outputs, the way the unit is shipped from FeelTech. Otherwise that switch stays in the safe/gounded position.
One more note; The sticker on the bottom of the unit is printed on an ink-jet printer. If it gets wet, it will bleed and smear.
Back when I was in school I too attempted to ground the DC outputs of a full bridge rectifier. Consider it a right of passage :D
I received the same power supply that you did.
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Who is going to contact FeelTech about the power issue?
See in the thread above for contact details of the company FeelTech.
I don't have all the details of the power issue at hand, and believe it would be better if the OP of the power issue takes the initiative.
I just sent an email to Carl at Feeltech (their sales manager for foreign business) describing the problem and asking them to suggest a fix. At present, a 2-pin polarized AC replacement connector or 3-pin AC connector with DC ground connected to earth/safety-ground seems like the best solution. It would be nice if they could identify a connector that fits the case without modification.
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A standard 3 prong plug will require mods to the case.
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Would an ordinary 50/60 Hz mains transformer with linear regulators solve the leakage problem as transformer circuits typically do not use Y-capacitors? For the 5V rail an simple buck-converter might be a nice solution if the heat should be a problem. The pictures show that the enclosure is almost empty, so there should be plenty of room for a small mains transformer and linear regulators + 5V buck converter.
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A standard 3 prong plug will require mods to the case.
That is true. I drilled a hole in the case. Inserted the 3 wire cord. Knotted it for strain relief. Dodgy but effective.
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Would an ordinary 50/60 Hz mains transformer with linear regulators solve the leakage problem as transformer circuits typically do not use Y-capacitors? For the 5V rail an simple buck-converter might be a nice solution if the heat should be a problem. The pictures show that the enclosure is almost empty, so there should be plenty of room for a small mains transformer and linear regulators + 5V buck converter.
It is a possible solution and has been discussed. Check out some prior entries.
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An IEC320-C6 power inlet jack (like this one with the mounting flanges) will fit with just a tiny bit of cutting to make room for the third wire. It's the exact same width as the two-conductor jack I removed from the FY3324S. Some sellers call them "power entry jacks".
http://www.amazon.com/Black-IEC320-Inlet-Power-Socket/dp/B008X0WET4 (http://www.amazon.com/Black-IEC320-Inlet-Power-Socket/dp/B008X0WET4)
I personally used an IEC320-C14 jack (in a similar style with the mounting wings). That one took quite a bit of cutting. I kinda wish had waited, but the C14 arrived at my doorstep first, and I was impatient to mod my function generator. The C14 is overkill for something that draws less than 100mA of AC current.
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For those who are unsure wether to ground their function gen or not:
In this thread you can see that a lot of higher priced function generator like Rigol DG1032z do not have floating, but earth grounded outputs:
https://www.eevblog.com/forum/testgear/function-gens-with-floating-outputs/ (https://www.eevblog.com/forum/testgear/function-gens-with-floating-outputs/).
This of course does not help you, if you acutally need floating outputs and bought the device for such a purpose.
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My old IEC F34 actually has a little thumbscrew screw that you can tighten to connect the earth ground, or loosen to make it floating. I guess you can just as easily insert a three prong to two prong adapter when you wanted make it floating (for this FeelTech). Note never float your scope...
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My old IEC F34 actually has a little thumbscrew screw that you can tighten to connect the earth ground, or loosen to make it floating. I guess you can just as easily insert a three prong to two prong adapter when you wanted make it floating (for this FeelTech). Note never float your scope...
Ah, the Indestructible Interstate, also sold under the Racal-Dana brand. :-+
I have an IEC F43 "High Voltage" FG, and it has a slide switch on the back panel that selects Signal Ground to be Isolated (floating) or Chassis (grounded). All the BNC connectors are isolated from the chassis ground, unless this switch is in the "grounded" position. On mine I installed a front panel switch in parallel to this factory switch since I can't easily reach around to the the back of my instrument stack.
Somehow I thought that the F34 also had this back-panel switch, but I can't seem to find my F34 to check.
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Yeah, I love my F34. It was my first function gen, and I fixed it up myself...
I has a thumbscrew, rather than a switch.
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added 3wire power socket, but, instead short connection of central ground power wire and the device ground I use a 2.2mf 250V capacitor (110V wall power) voltage drop to 0.1V , did I made it right ?
still some noise at range 10-20 mV in the output signal, some 10-20 MHz
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Spectrum 1K , output 6V indicated on device, equal 0db input for sound card, recorded by Xonar, -120db. FFT max resolution 8M.
(green, white - both channels, but they equal )
THD calculated up to 15 harmonics: 0.131424857 %
0.15% i would say ...
(http://i.imgur.com/NQEwISB.png</a>)
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I'm not convinced this ghost voltage is even a safety issue, rather a natural side affect of how switching power supplies are designed… Still… I FEEL better leaving the switch I installed in the setting that connects the FG's DC ground to mains-earth ground. I'll leave it in that position unless I have a reason not to.
I'm not convinced it's a safety issue either although having looked at the internals, I'd be completely shocked (no pun intended) if the design meets safety standards (UL, CE, etc.). Assuming the EMC cap that bridges the HV and SELV sides is a Y1 rated capacitor and suitably sized (smaller than ~1-5nF iirc), and ignoring other questionable mains safety issues, then IEC950 requirements for class II (unearthed) power supplies limit maximum leakage (touch current) to 0.25mA (much lower than the 4-6mA GFCI trip level). I measured mine and with the power on it has 32uA of touch current and with power off it is 110vac at 50uA; in either case, it's well below the 250uA limit.
However, even if it is not a safety hazard, this is *definitely* not what I want from test equipment that I will be connecting to sensitive electronic equipment whose ground may be earth referenced. The DC outputs of all of my other test gear float with respect to AC mains or are earth grounded. Fortunately, the fix is straightforward.
So far, the manufacturer has not responded to my inquiries.
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An IEC320-C6 power inlet jack (like this one with the mounting flanges) will fit with just a tiny bit of cutting to make room for the third wire. It's the exact same width as the two-conductor jack I removed from the FY3324S. Some sellers call them "power entry jacks".
http://www.amazon.com/Black-IEC320-Inlet-Power-Socket/dp/B008X0WET4 (http://www.amazon.com/Black-IEC320-Inlet-Power-Socket/dp/B008X0WET4)
Thanks Texacate, I've ordered the same jack from Amazon (for $5.74 w/free shipping); the same jack is available on eBay a little cheaper ($3.42 w/free shipping) with a little slower shipping: http://www.ebay.com/itm/Black-3-Pin-IEC320-C6-Inlet-Plug-Power-Socket-AC-250V-2-5A-/311080812333 (http://www.ebay.com/itm/Black-3-Pin-IEC320-C6-Inlet-Plug-Power-Socket-AC-250V-2-5A-/311080812333)
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Hi All!
A few days ago I received my FY3224s. What a little beauty :)
For safety I placed a 3-pole power inlet and made it switchable (isolated / chassis) on the back side.
The same for the (sometimes annoying) beeper.
Nevertheless, for $60 it's a nice generator!
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Hi All!
A few days ago I received my FY3224s. What a little beauty :)
For safety I placed a 3-pole power inlet and made it switchable (isolated / chassis) on the back side.
The same for the (sometimes annoying) beeper.
Nevertheless, for $60 it's a nice generator!
What is wrapped up in the silver duct tape?
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Hi All!
A few days ago I received my FY3224s. What a little beauty :)
For safety I placed a 3-pole power inlet and made it switchable (isolated / chassis) on the back side.
The same for the (sometimes annoying) beeper.
Nevertheless, for $60 it's a nice generator!
What is wrapped up in the silver duct tape?
500 gr. lead ;)
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question: to use a capacitor inline a ground wire, instead direct connection, is it correct ? or better to use a switch ?
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question: to use a capacitor inline a ground wire, instead direct connection, is it correct ? or better to use a switch ?
I have no idea. I wonder how high-end function generators (with floating output options) are designed? It's cool this thing has so much room inside for all these hacks/upgrades/customizations.
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I find the rotary knob has a lot of 'backslash'. Is that a common "feature"?
It seems to be not very simple to replace.
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Got my FY3224S yesterday :)
I already replaced the power plug against a 3 wire one and added a switch for selecting between earth grounded and floating. After using it for a while I already thought about a buzzer switch, too ...
Rev. 2.0 is displayed during startup. Are there any known Firmware updates - or does the original firmware exist as a file and is programmable via USB or JTAG?
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Hi everybody!
I have recently bought on the aliexpress the FY3224S rev. 2, unfortunately it came to me without the CD, so I don't have possibility to upload my own waves.
If someone has the software for the FY3200S family, please could you share it?
Sincerely yours,
bobofrut
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Hi everybody!
I have recently bought on the aliexpress the FY3224S rev. 2, unfortunately it came to me without the CD, so I don't have possibility to upload my own waves.
If someone has the software for the FY3200S family, please could you share it?
Sincerely yours,
bobofrut
http://www.file-upload.net/download-11525330/FY3224S_CD.zip.html (http://www.file-upload.net/download-11525330/FY3224S_CD.zip.html)
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Hi everybody!
I have recently bought on the aliexpress the FY3224S rev. 2, unfortunately it came to me without the CD, so I don't have possibility to upload my own waves.
If someone has the software for the FY3200S family, please could you share it?
Sincerely yours,
bobofrut
http://www.file-upload.net/download-11525330/FY3224S_CD.zip.html (http://www.file-upload.net/download-11525330/FY3224S_CD.zip.html)
Thank you so much!
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FWIW, I have the same contents on my CD, received a few days ago, only with the addition of Foxit Reader. Did a bit-by-bit comparison.
It took around an hour to copy, so it's probably a really low-quality medium.
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FWIW, I have the same contents on my CD, received a few days ago, only with the addition of Foxit Reader. Did a bit-by-bit comparison.
It took around an hour to copy, so it's probably a really low-quality medium.
I removed the Foxit Reader to reduce size of the zip file.
In the FY3200 Directory is even a documentation of the USB Commands.
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Got my FY3224S yesterday :)
I already replaced the power plug against a 3 wire one and added a switch for selecting between earth grounded and floating. After using it for a while I already thought about a buzzer switch, too ...
Rev. 2.0 is displayed during startup. Are there any known Firmware updates - or does the original firmware exist as a file and is programmable via USB or JTAG?
My unit boots to Rev 2.0 firmware also. I'm not aware that firmware updates have been publicly released for the FY3224S. It would be nice. If anyone knows, please post the info here!!!
I was looking at the output on my oscilloscope, and I must say... Overall, I'm VERY impressed! The waveforms look super clean. I feel its a great value for the money.
The only things I can find that make this thing less-than-perfect are:
1) There is a small amount of phase drift between the two channels when frequencies are set to integer multiples of each other. (When set to the exact same frequency they seem to be locked)
2) Slight jitter on the trailing edge of square waves.
3) A teeny-tiny bit of crossover distortion when a waveform crosses zero volts. Im wondering if this is due to the input voltage offset of the op-amp driving the BNC outputs vs something in the DtoA conversion.
4) I'm not liking that when you select the [WAVE] button, it immediately advances to the next waveform, I would rather it just activate the waveform adjustment feature, and wait for me to turn the knob or hit the arrow keys to change the waveform.
These are all minor annoyances. I'm super happy about how well the FY3224S performs. It's awesome.
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One other minor annoyance:
5) I wish the duty cycle of a triangle wave was settable. Your only choices are pure triangle (duty cy == 50%), saw tooth (duty cy >= 51%) , and reverse saw tooth (duty cy <= 49%). It would be nice if I set the duty cycle to 75%, Then the ramp-up time would be 75% of the period, and the ramp-down time would be 25% of the period.
It seems like some of these annoyances could be correctable in firmware...
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Who is going to contact FeelTech about the power issue?
See in the thread above for contact details of the company FeelTech.
I don't have all the details of the power issue at hand, and believe it would be better if the OP of the power issue takes the initiative.
I just sent an email to Carl at Feeltech (their sales manager for foreign business) describing the problem and asking them to suggest a fix. At present, a 2-pin polarized AC replacement connector or 3-pin AC connector with DC ground connected to earth/safety-ground seems like the best solution. It would be nice if they could identify a connector that fits the case without modification.
Did you receive any feedback from FeelTech in the mean time?
Maybe you could send a reminder, and also point their sales manager to this thread in particular.
FeelTech might get their act together if they realize that this thread, for which I proudly am the OP :),
has been viewed more than 28.000 times :)
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Would anyone like to validate my crossover distortion measurement ? See the attached photo.
I have set the FG to generate a 2.3kHz 5v triangle wave. I'm not sure the exact frequency or voltage matters, it's just what I was working with at the time. Ive seen in on Sine, and other waveform setting too. As mentioned earlier, overall, the wave forms look quite clean. And a few post back someone even measured the hormonic distortion levels. But if you zoom WAY in, you can find some crossover distortion.
The four pictures are of the same function generator setting, just zooming into the zero volt crossing on my oscilloscope.
(https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/?action=dlattach;attach=221310;image)
1st photo, upper-left: you can't see any crossover distortion. I've circled the area in red. (BTW, it happens at every zero-crossing, leading edge and training edge, though I've only circled one of them.)
2nd photo, upper-right: It's just barely starting to become visible. I'm not sure the photo will show it, but again I've circled the area in red.
3rd photo, lower left: Zooming in further. The crossover distortion is clearly visible as a zig-zag. We're also starting to see the quantization artifacts that all DDS function generators exhibit.
4th photo, lower-right: I'm fully zoomed in. The zig-zag at the zero crossing is measured to be roughly 1 division = 5mV. You can see some ringing too. However I'm not sure if that is coming from the function generator, or my setup. I did terminate the BNC cable with a 50ohm load to minimize cable reflections.
I'd be very curious to know what similar measurements look like using a high-end function generator.
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Would anyone like to validate my crossover distortion measurement ? See the attached photo.
I have set the FG to generate a 2.3kHz 5v triangle wave. I'm not sure the exact frequency or voltage matters, it's just what I was working with at the time. Ive seen in on Sine, and other waveform setting too. As mentioned earlier, overall, the wave forms look quite clean. And a few post back someone even measured the hormonic distortion levels. But if you zoom WAY in, you can find some crossover distortion.
The four pictures are of the same function generator setting, just zooming into the zero volt crossing on my oscilloscope.
1st photo, upper-left: you can't see any crossover distortion. I've circled the area in red. (BTW, it happens at every zero-crossing, leading edge and training edge, though I've only circled one of them.)
2nd photo, upper-right: It's just barely starting to become visible. I'm not sure the photo will show it, but again I've circled the area in red.
3rd photo, lower left: Zooming in further. The crossover distortion is clearly visible as a zig-zag. We're also starting to see the quantization artifacts that all DDS function generators exhibit.
4th photo, lower-right: I'm fully zoomed in. The zig-zag at the zero crossing is measured to be roughly 1 division = 5mV. You can see some ringing too. However I'm not sure if that is coming from the function generator, or my setup. I did terminate the BNC cable with a 50ohm load to minimize cable reflections.
I'd be very curious to know what similar measurements look like using a high-end function generator.
On my FS3224s the same:
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Got my FY3224S yesterday :)
I already replaced the power plug against a 3 wire one and added a switch for selecting between earth grounded and floating. After using it for a while I already thought about a buzzer switch, too ...
Rev. 2.0 is displayed during startup. Are there any known Firmware updates - or does the original firmware exist as a file and is programmable via USB or JTAG?
Boot the FY3224s with the rotary knob depressed. When booted, release knob ==> NO BEEP ;-)
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Would anyone like to validate my crossover distortion measurement ? See the attached photo.
I have set the FG to generate a 2.3kHz 5v triangle wave. I'm not sure the exact frequency or voltage matters, it's just what I was working with at the time. Ive seen in on Sine, and other waveform setting too. As mentioned earlier, overall, the wave forms look quite clean. And a few post back someone even measured the hormonic distortion levels. But if you zoom WAY in, you can find some crossover distortion.
The four pictures are of the same function generator setting, just zooming into the zero volt crossing on my oscilloscope.
1st photo, upper-left: you can't see any crossover distortion. I've circled the area in red. (BTW, it happens at every zero-crossing, leading edge and training edge, though I've only circled one of them.)
2nd photo, upper-right: It's just barely starting to become visible. I'm not sure the photo will show it, but again I've circled the area in red.
3rd photo, lower left: Zooming in further. The crossover distortion is clearly visible as a zig-zag. We're also starting to see the quantization artifacts that all DDS function generators exhibit.
4th photo, lower-right: I'm fully zoomed in. The zig-zag at the zero crossing is measured to be roughly 1 division = 5mV. You can see some ringing too. However I'm not sure if that is coming from the function generator, or my setup. I did terminate the BNC cable with a 50ohm load to minimize cable reflections.
I'd be very curious to know what similar measurements look like using a high-end function generator.
On my FS3224s the same:
Thats interesting, I never noticed that, I will take a look at mine later on this week. I will post my findings, good spot. :-+
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Boot the FY3224s with the rotary knob depressed. When booted, release knob ==> NO BEEP ;-)
Doh! I should have read the user manual more carefully. It's documented on the second to the last page. Thanks for pointing this out!
On my FS3224s the same:
Thanks for checking my observation. Does anyone own a high-end function generator and is willing look at crossover distortion? I wonder how our little beast compares?
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Well.... I set up my MingHo MHS 5200A, which is definitely _not_ a "high end" FG, and did not see anything like the crossover distortion shown up above.
I thought that the MHS5200A was pretty much equivalent to the FeelTech model, same price point and very similar specs, but there are some significant differences. Coarser quantization, apparently.
I used a 2.3 kHz 5V triangle wave setting on the FG, and a BNC patch cable with 50 ohm through-terminator at the scope. Same result (except for amplitude) without the through-terminator. I've noticed before that the amplitude with 50 ohm termination doesn't show up on the scope at the same value as set on the FG. But with no terminator the measured amplitude is the same as set on the FG. Weird, since the FG is supposed to have 50 ohm outputs, I thought. In either case there is no sign of that crossover glitch.
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I thought that the MHS5200A was pretty much equivalent to the FeelTech model, same price point and very similar specs, but there are some significant differences. Coarser quantization, apparently.
Thanks for checking. I agree, the two FGs do have some significant differences.
I believe the coarseness of the quantization can be explained by the DAC resolution and the waveform length specs.
Specification FY3200S MHS-5200A
Waveform Resolution 12 bits 8 bits
Waveform length 2048 1024
I chose the FY3224S over the MHS-5200A pretty much based the above two specs. If I get the chance, I may open my FY3224S and probe upstream in the signal path/closer to the DAC output. I'm curious to see if the crossover distortion is being introduced by the output drivers, or it starts right at the DAC. Anyway. Thanks for the datapoint!
BTW, you should see a lower amplitude at the scope when you use a 50 ohm load, because it forms a voltage divider with the FG's 50 ohm impedance at the BNC output. It should be exactly half (assuming precisely matched 50 resistors) of the unterminated value.
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C10 is not a mistake. It is a common way to reduce emissions. It also causes the leakage from mains to the generator's outputs.
Hello everyone. I am relatively new to this forum (and blogs in general). I am a retired EE, so I should understand more than I do, but actually I was more of a software engineer for the last 20 years or so, and I never was very good at analog. I am interested in getting back into "playing around" with electronics again, and I am thinking of buying an oscilloscope soon. That research brought me to this forum on signal generators, and I was so impressed by the FY3224S that is being discussed here (for the price), that I went ahead and ordered one.
I have read most of the posts regarding the safety issue with AC voltage present on the shields of the BNCs, but I am not sure that I understand where it is coming from. There was a schematic of the power supply in one of the posts that "nctnico" responded about above. (It may not be the schematic of the actual supply in the FY3224S, but I got the idea that it was very similar to it).
Can someone explain how C10 in that schematic cause AC voltage from the mains to be introduced on the output ground (shields of BNCs)? It seems to me that C10 is connected to filtered DC at that point. If that was the cause of the AC voltage, why does reversing the AC plug reduce the voltage seen on the BNC shields?
Thanks.
PS: I also went ahead and ordered a 3 wire AC socket so I can tie the signal grounds to earth ground like several others here are doing. That seems like a good idea.
+ Attachments and other options
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I finally replaced the AC power jack on my FY3224S with a 3-prong jack and connected the earth/safety ground to the DC ground. This completely eliminated the unwanted AC high voltage on the DC outputs. There is no measurable effect on power consumption of the unit so from my perspective, this solves the problem. Replacing the jack is straight-forward and only required slight filing of the case (the filing is invisible once the new jack is inserted). Please note: if you don't have the appropriate experience with AC mains voltages, you shouldn't even open this box.
With respect to safety, I don't think this ever posed a human-safety issue because the touch current is very low. However, the high voltages on the output may be a hazard to sensitive equipment, even at very low currents, so connecting the DC ground to earth ground seems like a good solution.
For those who asked, I never heard back from Feeltech.
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C10 is not a mistake. It is a common way to reduce emissions. It also causes the leakage from mains to the generator's outputs.
Can someone explain how C10 in that schematic cause AC voltage from the mains to be introduced on the output ground (shields of BNCs)? It seems to me that C10 is connected to filtered DC at that point. If that was the cause of the AC voltage, why does reversing the AC plug reduce the voltage seen on the BNC shields?
Yes C10 is point where the voltage in injected. What is really AWEFUL in that specific schematic is their usage of that stupid earth-ground symbol on the primary side. (IE the symbol on the node connected to one output of the bridge rectifier diodes). That node is certainly NOT at the same potential as the real earth ground. If you probe it (relative to true earth ground on your oscilloscope), you will see it looks like half-recitifed sine wave of about 55 volts. And if you accidentally connect that node to the real earth ground (via the 3rd prong on a power plug OR the ground clip on your O-scope), your power supply circuit board will fry in an instant! (and perhaps your scope too). Yes the voltage across the big filter cap C2 is relatively stable DC, but its riding on top of a real 55v half-wave rectified, high energy voltage (referenced to the true earth ground potential).
C10 couples some of that voltage onto the LOW energy DC ground connected to the BNC jack, unless you bleed it off by earth grounding the DC ground node.
Oh, one other AWEFUL thing about that schematic, it looks like that node is directly connected the mains neutral wire. On the real power supply, that node is NOT connected to mains neutral. If it was actually wired the way it's drawn... Boom! You'll forward bias one of the bridge diodes with a boat-load of current (when the Line drops to -55v relative to the Neutral)
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I have contacted FeelTech about the safety issue where the signal generator is not properly grounded.
I also pointed them to the crossover distortion measurement issue.
Are there other pending firmware and hardware issues that are annoying?
It's hard to find them in this thread, as they are spreaded around, and there is no overall issues list.
If someone can make an overview of other pending firmware and hardware issues,
then I can also forward these issues to the FeelTech engineering department.
I could maintain an issues list at the start of the thread, as I am the Original Poster of this thread.
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I received my FeelTech FY3224S Generator this week from BangGood.com. Shipping only took about 10 days, and everything looks and works fine. I did replace the AC input connector with a 3 prong type and installed a switch to allow me to connect the earth ground to the DC ground; as suggested by several others here in this forum. Thanks to everyone for the help with this!
Does anyone know if there is a way to configure this unit so that the CH1 and CH2 outputs are NOT enabled when you first power it up? (Mine came with the Rev 2.0 firmware).
Thanks.
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According to the manual, one can program 20 different sets of waveform settings (waveform type, amplitude, frequency, etc.) with setting #0 as the one it uses for the power-on state. However, I don't see any attributes such as "Ch1/Ch2 enabled/disabled" that can program into save/load memory. Sorry. I agree, disabled on power-up would be better.
Pascal, please add this to your list. My other 5 minor gripes were listed earlier.
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I have received feedback from FeelTech, and they are going to bring their Engineering Manager in contact
with me. They look forward to work with me on further improving their product.
I informed them that the community on the EEVBlog forum has given me the task to act as the main interface with FeelTech, to report software bugs and other issues in the FeelTech FY3224S product.
This could mean that we can together further improve the product! Great news!
I will keep you informed after their Engineering Manager has reached out to me.
In the mean time, Texacate, could you list your 5 minor gripes in one small summary and add it here
as a response?
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https://www.youtube.com/watch?v=9o5MzTOzZo4 (https://www.youtube.com/watch?v=9o5MzTOzZo4)
I will be doing a linear power supply modification to mine (with a video) in the next few days.
Banggood gave me a discount code to share with everyone if they are interested in purchasing:
Product Link: http://bit.ly/1LLPFD6 (http://bit.ly/1LLPFD6)
Use Coupon Code "FY3224S"
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I have contacted FeelTech about the safety issue where the signal generator is not properly grounded.
I also pointed them to the crossover distortion measurement issue.
The distortion is a classic issue with R2R ladders when the MSB changes state. There is no DAC chip in this device, it's a resistor ladder with analogue switches. Effectively the errors add from all of the resistors in the ladder and do not match the value of the MSB resistor.
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That was a great video. :-+
Two things that still have me stumped though. :-//
1. Did you ever work out what the batteries were doing in the box ?
2. Why the hell have I not yet subscribed to your channel ?
It's up the top in my favourites list and I've been a fan for quite a while, I will get this looked into and rectified immediately, no excuse for it at all. I have a big list of stuff ready to order from Bangood and it's nice to see them giving some back by supporting you and hopefully taking notice of your findings.
Thank you, well done :)
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That was a great video. :-+
Two things that still have me stumped though. :-//
1. Did you ever work out what the batteries were doing in the box ?
2. Why the hell have I not yet subscribed to your channel ?
It's up the top in my favourites list and I've been a fan for quite a while, I will get this looked into and rectified immediately, no excuse for it at all. I have a big list of stuff ready to order from Bangood and it's nice to see them giving some back by supporting you and hopefully taking notice of your findings.
Thank you, well done :)
The batteries are a complete mystery! Looks like someone accidentally packed them in the box.
The plan now is to modify the sig gen with a linear power supply and also add in an isolator for the USB connection.
Thanks :-+
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@SteveyG, Would you recommend that function generator for a beginner that is following along the Learning Arts of Electronics book? I noticed that the book is using both an Scope and Func Gen on a lot of the labs and this seems like a decently priced one for a person on a small budget.
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I would recommend it for you. It would probably be a good idea to put a linear power supply in it, but it is a great unit for the price.
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SteveyG, let us know if you find a small, economical linear power supply capable of +5v +12v -12v. The only ones I know of are targeted toward the eurorack modular analog synthesizer market. And those only meet the "small" criteria. They cost more than this function generator does. My thoughts were using a +/- 15V switching supply (such as Meanwell PD-2515) followed by some LM7812s and a LM7805. But I guess I'm a still a bit unclear regarding the value a linear supply would add to the FY3224S, over the switching power supply it already has. Is there a particular performance spec that would benefit if you replaced the switching power supply with a linear one?
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SteveyG, . But I guess I'm a still a bit unclear regarding the value a linear supply would add to the FY3224S, over the switching power supply it already has. Is there a particular performance spec that would benefit if you replaced the switching power supply with a linear one?
A linear supply would give complete isolation from the mains.
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I am putting together a supply based on one of these for the +/-12v and a regular LM317 module for the 5V.
http://www.ebay.com/itm/172120955716?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/172120955716?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
All this connected to a 15V transformer through a mains fuse. Separate switch to control earth ground.
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A transformer such as this?
http://www.ebay.com/itm/1pc-110VAC-5W-Power-Supply-Transformer-15V-X-2-/322069838238 (http://www.ebay.com/itm/1pc-110VAC-5W-Power-Supply-Transformer-15V-X-2-/322069838238)
What are you thoughts on a fully shielded transformer such a this (rather expensive) one?
http://www.ebay.com/itm/Bourns-30v-Center-tapped-Shielded-Audio-Power-Transformer-15v-0-15v-NOS-4-1-/311606745614 (http://www.ebay.com/itm/Bourns-30v-Center-tapped-Shielded-Audio-Power-Transformer-15v-0-15v-NOS-4-1-/311606745614)
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I got a $3 one from my local store. I do need to measure the current the FeelTech uses. Have you done so?
I think a 5W tranny would likely be way overkill. But better to overbuild than to under build. Again need to measure the current to decide if mine will work or not.
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I have never directly measured the 12v supply current. I did measure the AC power on the mains with a watt-meter one time. As I recall it was ~0.5W idle, and ~3 watts driving only one channel at 10v p2p sine into into a 50 ohm load.
Looking at it from a completely different angle: Its pretty easy to calculate worst-case power needed to drive the BNC outputs. I don't recommend actually doing this but... Assume we abuse the thing and make it drive +10V DC (open circuit), but short the BNC outputs with nothing but the FG's internal 50 ohm impedance to regulate the output current. That works out to 200mA of current, or 2 Watts per channel, times two channels = 4 Watts total. If we're not quite that abusive, and always use 50 ohm minimum load, then the max power needed by the output drivers drops from 2W per channel to 1W per channel = 2W total. Throw in another watt for losses, the FPGA, and the display and such, and you're back up to ~3W.
Im guessing a 5W transformer would be in the right ball park.
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I would recommend it for you. It would probably be a good idea to put a linear power supply in it, but it is a great unit for the price.
What would be a good linear power supply? I am in Europe and i don't have ground wall plugs except Kitchen / Bathroom.
Best Regards
Marcus
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I remember that in Sweden! :)
In Norway it is actually a harder requirement, ground plug everywhere. Just like in Belgium!
Sweden is a bit behind here =)
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I remember that in Sweden! :)
In Norway it is actually a harder requirement, ground plug everywhere. Just like in Belgium!
Sweden is a bit behind here =)
I think new production has requirements of ground plugs everywhere.
Think it was enforced at the 90s, but i am not 100% sure about that.
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SteveyG, let us know if you find a small, economical linear power supply capable of +5v +12v -12v. The only ones I know of are targeted toward the eurorack modular analog synthesizer market. And those only meet the "small" criteria. They cost more than this function generator does. My thoughts were using a +/- 15V switching supply (such as Meanwell PD-2515) followed by some LM7812s and a LM7805. But I guess I'm a still a bit unclear regarding the value a linear supply would add to the FY3224S, over the switching power supply it already has. Is there a particular performance spec that would benefit if you replaced the switching power supply with a linear one?
I'm just recording some of the bits for the next video. My plan is to use a small transformer and some regulators. I didn't see any off the shelf linear modules with the voltages we need.
The main reason for the linear supplies is because the transformers provide proper isolation from the mains. The leakage currents from the switching power supply on these units may cause damage to your circuitry.
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Linear power supply has also disadvantages, isn't it?
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Linear power supply has also disadvantages, isn't it?
Efficiency, size, weight and maybe cost.
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Steveyg: Do you see those lm317/lm337 eBay modules I posted earlier in this thread. Should let you get +/-12V from your transformer rather easily and cheaply...
Love your channel, BTW.
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Looking forward to your linear supply upgrade, Steve.
What frequency reference does this generator use and would it be a major undertaking to swap it out or hack in an external reference connection? I have an OCXO in my counter that would be nice to pipe into the generator.
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Looking forward to your linear supply upgrade, Steve.
What frequency reference does this generator use and would it be a major undertaking to swap it out or hack in an external reference connection? I have an OCXO in my counter that would be nice to pipe into the generator.
bitseeker = Frequent Contributor and Creative Contributor :-+
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Thanks, Pascal. If only I had enough time to implement what's generated by that creativity. At least there's no shortage of things to make, hack or otherwise improve. ;D
This unit is a cool platform for tinkering. An external clock input would be quite nice.
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If I recall the clocking is handled by the FPGA (which has its own crystal, maybe 24MHz, don't recall), not by aseparate timing crystal per se. Making it really difficult to convert for an external clock.
Anybody confirm this? It was a while back that I checked.
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If I recall the clocking is handled by the FPGA (which has its own crystal, maybe 24MHz, don't recall), not by aseparate timing crystal per se. Making it really difficult to convert for an external clock.
Anybody confirm this? It was a while back that I checked.
It looks like the 24MHz crystal is shared between the FPGA and the MCU. An external reference may be possible with a PLL though, although I don't have enough time for that modification just yet.
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No worries. Good to know it's possible!
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Regarding the 1mA leakage current from mains an a new inear power supply: I found an old 220V / 220V isolating transformer in my stock. This at least can reduce the issue without any changes within the units. The transformer is way too big (60VA) and has a leakage current of ca. 50µA, probably due to capacity coupling from primary to secondary. It is a one chamber transformer.
Maybe we can find a smaller and cheap isolating transformer, if possible with two chambers. Ore maybe two cheap mains to 15V or so in serie circuit (mains -> low voltage -> mains).
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SteveyG's linear power supply mod is up now:
https://www.youtube.com/watch?v=ML-lmuHoh-0 (https://www.youtube.com/watch?v=ML-lmuHoh-0)
How is the heat build up inside the case? I didn't see much in the way of ventilation. Are the slots on the side open? They looked decorative, but could be cut open.
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How is the heat build up inside the case? I didn't see much in the way of ventilation. Are the slots on the side open? They looked decorative, but could be cut open.
I really need a FLIR One, but the calibrated finger says the heatsink was between 40 and 50°C at full load. The 15V transformer was probably the hottest part, after 30 mins at full output into 50R that transformer was a bit too hot to touch. I will make some measurements but I think a 40mm fan may be needed, however it definitely doesn't need to run very fast.
The vents are open, on the bottom half only, so kinda pointless on their own. You could probably drill a matrix of holes on the bottom and top which would be sufficient for convection to draw outside air in.
Discount code valid for May 2016 @banggood.com is here: https://sdgelectronics.co.uk/uncategorized/fy3224/
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Back in the 90s I had a USR 33.6k modem (state of the art at that time) which would overheat and reduce its speed. I drilled a bunch of holes in the top and bottom and it worked a treat. It did look a little stupid :-DD
Seriously, I was thinking the same thing, as I finalize my linear supply design. Would be nice to be able to get the regulators on the side of the case with a heat sink mounted on the back or side. I would really rather avoid another fan...
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Those small mains transformers are very inefficient to begin with so together with the linear regulators you'll need more airflow. Still you might get away with drilling some extra holes at the top in the rear cover plate so air can flow in from the bottom and flow out at the top of the instrument.
I'll just ground my FY2306 instead of replacing the PSU and be done with it. After all the USB interface isn't isolated either. While at it I'll also remove the tilt stand because it makes the box uneven.
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The vents are open, on the bottom half only, so kinda pointless on their own. You could probably drill a matrix of holes on the bottom and top which would be sufficient for convection to draw outside air in.
At least it has them on the bottom. That's a good start.
Still you might get away with drilling some extra holes at the top in the rear cover plate so air can flow in from the bottom and flow out at the top of the instrument.
Venting the top of the rear plate was exactly what I was thinking. Functional without getting ugly. Not that it's a beautiful case, mind you, but drilling the top cover would be less aesthetically pleasing to my eye.
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Venting the top of the rear plate was exactly what I was thinking. Functional without getting ugly. Not that it's a beautiful case, mind you, but drilling the top cover would be less aesthetically pleasing to my eye.
Not just that but there is also the risk of stuff falling into the generator. I always try to prevent having holes in a top cover.
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Those small mains transformers are very inefficient to begin with so together with the linear regulators you'll need more airflow. Still you might get away with drilling some extra holes at the top in the rear cover plate so air can flow in from the bottom and flow out at the top of the instrument.
I'll just ground my FY2306 instead of replacing the PSU and be done with it. After all the USB interface isn't isolated either. While at it I'll also remove the tilt stand because it makes the box uneven.
Earthing the PSU is definitely a good (cheap) option, and yes, the smaller transformers are not the best for efficiency.
My expensive TTi sig gen is obviously earthed as are all the BNCs. The USB interface will be isolated in the next video though - I think having this one able to float might be handy.
Venting the top of the rear plate was exactly what I was thinking. Functional without getting ugly. Not that it's a beautiful case, mind you, but drilling the top cover would be less aesthetically pleasing to my eye.
Not just that but there is also the risk of stuff falling into the generator. I always try to prevent having holes in a top cover.
I think I'll go for the noisy option of a fan on the rear panel. It doesn't seem like it'll need much airflow and half of the Agilent gear on the bench has whiny fans anyway :-//
Holes in the top cover could be an option if you put some speaker grille fabric on the inside for example, but that obviously restricts airflow.
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Reading about these heat issues I most probably will opt for an isolation transformer. I can start with my 60VA. But a 26VA isolation transformer is <14 EUR new. And 26VA should be sufficient for a 5 to 6VA instrument. Insert it in an (old) housing, add a fuse holder and a power cord and that's it.
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How about putting a small isolation transformer inside the case? Or 2 low voltage transformers back-to-back.
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Reading about these heat issues I most probably will opt for an isolation transformer. I can start with my 60VA. But a 26VA isolation transformer is <14 EUR new. And 26VA should be sufficient for a 5 to 6VA instrument. Insert it in an (old) housing, add a fuse holder and a power cord and that's it.
To be honest, an isolation transformer is not required unless you specifically want the AWG floating. If you connect the 0V on the PCB to mains earth you're fine from a current leakage point of view.
2x13.5V transformers may be available too which would cut down some of the dissipation.
Lots of options :-)
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How about putting a small isolation transformer inside the case?
Yes, e.g. ebay 181990291398 or similar. But I do not know if 88 x 53 x 48mm will fit into the case.
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To be honest, an isolation transformer is not required unless you specifically want the AWG floating.
Yes, this can be helpful in avoiding ground loops, e.g. in audio applications.
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I think I'll go for the noisy option of a fan on the rear panel. It doesn't seem like it'll need much airflow and half of the Agilent gear on the bench has whiny fans anyway :-//
Yeah, if you already have fans going in a bunch of instruments, adding a little one to the mix won't be noticeable.
Looking forward to the next vid, Steve. :-+
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An alternative could be to use a transformer with an 85V (or more) secundary winding (or 2 lower voltages in series). My generator says it will run from 85VAC or more.
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Ah, I see. Just put a 120->85+ or 240->85+ transformer before the existing supply. Yeah, it doesn't have to be 1:1.
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The closest (unexpensive but new and available in Germany) which I could find is
- 2 of Gerth EAN 2050001920652; 38 mm x 32 mm x 45 mm; 5.6VA; 2x30V (=120V); @5,50 EUR each = 11 EUR ; Safety-Transformer, IEC 61558-1 and 2-6; protection index IP 00; prepared for class I / II equipment; vacuum potted; max. admissible ambient temp. 70°C; 2 chamber safety-bobbin; test voltage 4.000 V ac; non short-circuit-proof; approval mark: VDE, ENEC 10
Looks good if it fits in the case.
otherwise the smaller "brother" (3 to 4 mm smaller in each dimension)
- 2 of Gerth EAN 2050001920355 ; 34 mm x 29 mm x 41 mm; 3.6VA (could be at the edge) @4,40 EUR each =8,80 EUR
Maybe you find something more appropriate or an option with a better availability in your country.
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Darn !!! ... I cold not stop :) ... just ordered one. Thanks for the discount code Steve !
It will probably make a nice addition to my old Tek FG504
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If one wants the transformer isolation mod be as small/light as possible, how much can you optimize the transformers, so that it still provides the current required by the fun.gen. and its output voltages allow to scale down the heatsink as well?
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@SteveyG
Regarding your request for questions in the latest vid:
Have you had a look at the generated waveform during transition to a different frequency? Does it still glitch with the latest firmware the way it did last year as reported in post #45 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg739365/#msg739365)? Hopefully, that was something that could be rectified via firmware update.
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How about putting a small isolation transformer inside the case?
Yes, e.g. ebay 181990291398 or similar. But I do not know if 88 x 53 x 48mm will fit into the case.
Inside, you have about 63mm height. Based on that, with the power supply that was originally fitted inside the case to my signal generator, there is enough room. I see some people have slightly larger PSUs, but it should still fit.
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@SteveyG
Regarding your request for questions in the latest vid:
Have you had a look at the generated waveform during transition to a different frequency? Does it still glitch with the latest firmware the way it did last year as reported in post #45 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg739365/#msg739365)? Hopefully, that was something that could be rectified via firmware update.
Unfortunately, yes it does. It is however fixable by FW - there is no hardware limitation that I can conceive of that would cause this.
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Thanks for the confirmation, Steve. At least the transitions are smooth when it sweeps frequencies.
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How about putting a small isolation transformer inside the case?
Yes, e.g. ebay 181990291398 or similar. But I do not know if 88 x 53 x 48mm will fit into the case.
Inside, you have about 63mm height. Based on that, with the power supply that was originally fitted inside the case to my signal generator, there is enough room.
Thanks a lot for this info. So, the ebay 181990291398, 2 of Gerth EAN 2050001920652 or an elma TT EAN 4016138043341; 30VA; 15 EUR http://www.produktinfo.conrad.com/datenblaetter/500000-524999/514810-da-01-en-Trenntrafo_30VA.pdf (http://www.produktinfo.conrad.com/datenblaetter/500000-524999/514810-da-01-en-Trenntrafo_30VA.pdf) could just fit. So, we have some feasable and reasonable options.
I will order a signal generator and we will see how it looks like and then I will decide for the transformer.
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Regarding the USB isolation: Did anybody try an USB-Isolator based on ADuM4160 like ebay #141998972441?
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My unit arrived today. The Y-capacitor is approximately 1 nF and the leakage current between GND and PE is about 0.2mA. Power consumption at full load is approximately 8VA. So the 2 x 5,6VA transformers should be sufficient.
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Regarding the USB isolation: Did anybody try an USB-Isolator based on ADuM4160 like ebay #141998972441?
Probably no need to isolate the USB side of the UART-USB converter. I've been unwell last week so didn't get chance to do the next video on USB isolation - hopefully I'll get something out this week.
Steve
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I didn't get it guys. Why don't you just leave this thing unmodified? Where is the problem?
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I didn't get it guys. Why don't you just leave this thing unmodified? Where is the problem?
Some people -like me- have the urge to improve things. Call it a mild form of OCD >:D
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I've ordered my FY3224S and i'm already studying on how to made it better. Linear power supply and/or plug with gnd is a must, then i was searching on how to increase the power output, the output amplifier is a unit gain buffer? Maybe this opamp should be adeguate:
http://www.ti.com/product/LMH6321 (http://www.ti.com/product/LMH6321)
Can't wait to put my hands on it ;D
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Why don't you just leave this thing unmodified?
You are right. For most purposes it would work out of the box just fine. The capacitive coupling to mains is a good excuse to work on it. And many of us have fun doing something like that. Some want to do it right by setting up a solid power supply, other - like me - like to get rid of the leakage current with a minimum of effort. suum cuique.
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What about the other improvements, like improving the quality of the signal output?
Power circuit as such, is a NICE to have improvement, but further improving the signal output is more MUST have :)
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Thanks for your replies guys.
pascal_sweden note is also important.
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I've been unwell last week so didn't get chance to do the next video on USB isolation - hopefully I'll get something out this week.
Sorry to hear that, Steve. Something's been going around here as well. So far, I've dodged it. Hope you're feeling better soon!
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I didn't get it guys. Why don't you just leave this thing unmodified? Where is the problem?
Problem? Quirk? Bug? Deficiency? It depends on how you look at it. The bottom line is that this device can be better than it is and it doesn't cost a lot if you blow it up. So, it's a prime candidate for tinkering, whether you're doing it to learn, entertain yourself, help the community, etc.
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[ftp]Hello and sorry for my bad english. This is my first message here.
The power supply of my unit has +5V, +12V & -12V outputs, but only +11V & 11V are developped. So, the output at 20Vpp is slightly cutted in open ouput and the same at 8Vpp about 50 ohm load.
I thought rise turns number of +-12V coils, but this is hard and dangerous (transformer broke).
Finally, I changed the schottky diode of +5V output for a series group of four similar schottky diodes. This action rise voltage of +5V coil (not in the +5V out) in 1V aproximately and proportionaly in +-12V coils.
The ouput in +-12V outs is +-13V now and ouput in open circuit reach 20Vpp and 11Vpp about 50 ohm without problem.
More diodes rise more voltage but this could be dangerous for the output opamps. I reached +-18V but I went backwards.
The supply runs at 330KHz and is good idea to use only scottky diodes for this mod in +5V out.
The trigged output of certain number of pulses on main output (burst) is ok for peak audio power of amplifiers.
TTL out have very small rise time and is ok for longitude and impedance tests in transmission lines (TDR) with 1MHz and 1% duty.
Javier Muriedas (EA1AWY)
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Is there any advantages to modifiying this unit as SteveyG did in his Youtube video if you don't have grounded wall sockets?
Best Regards
Marcus
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That depends...
In your situation I would measure the voltage and the current between the signal generator and the BNC jack and my oscilloscope or power supply or other units I have on the bench. If there is no high voltage and just a few µA I wouldnt worry about threatening my DUTs.
On the other hand the insulation of the wires of built in transformer dos not look too good. So, an additional isolation transformer at least improves your personal protection against electrical shocks if the built in transformer would fail.
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Don't have the unit yet, haven't ordered it.
My Oscilloscope is connected to a PeakTech AC Power Supply which is an Isolation Transformer.
Overkill i guess but since don't have Ground Outlets in the apartment except Bathroom / Kitchen and i got it as a gift, i decided to use it to keep the Scope a bit safer.
Will most likely order the Function Generator plus the stuff that SteveyG are using.
Thanks for a quick response!
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If you don't have outlets with ground then the best thing to do is to get a power distribution bar with grounded outlets. Then at least all the grounds of the equipment is connected together. The residual AC voltage on a piece of ungrounded equipment is powerful enough to damage an input of a chip.
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@nctnico, Yeah, Power Supply and such are connected to a power bar so they are on the same ground loop, including the Isolation Transformer is on that.
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Gby said:
"Just for fun I made an 2048 point waveform that is 10 sine cycles. This way when commanding 6 MHz you actually try to output 60 MHz. I would say using this technique you get usable output up to the full FY3224S product of 24 Mhz. Above 30 MHz the amplitude drops and the phase lag increases rapidly. Below are my test results: "
I'd like know how you are do it and if you would put the file here.
Thanks
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electronauta,
I used a spreadsheet to make two columns of data. The first was just in numerical order and the second used a formula to create the value. The FY3200 expects the following for arbitrary waveform data:
1. 2048 points. So the first column was numbered 0 to 2047
2. Waveform values to be between 0 and 4095 (12 bits)
3. 0 corresponds to minimum Vout, 2048 counts correspond 0 Volts, and 4095 corresponds to maximum Vout
Assume column A is the 0 to 2047 numerical sequence and column B will be the arbitrary wave value. To get my example of 10 sinusoidal cycles over the 2048 points I used the following formula:
value in B1 = 2047*sin(10*A1*pi()/1024) + 2048
I attached a simple spreadsheet I made to do the above for anyone that wants to use it. This spreadsheet allows you to set the number of sine cycles and the phase that it starts at.
To get this waveform into the generator I used the Feeltech PC software. In the spreadsheet I copied the data column and in the Feeltech software I pasted the data. More specifically, in the Feeltech software I clicked on the "Text Window" tab and I pasted the data in the large blank text box. If you do this step correctly you should see the waveform shown in the graph in the lower right hand corner. The last step is to click the send button to get the waveform to be sent to the FY3200.
Please note that I was not able to get this software working to send the arbitrary waveform until I had just the right driver installed on my PC. Please my earlier post on page 1 on this thread for details.
Hope this all helps. Have fun.
gby
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electronauta got my interest in this generator again. Earlier I had noted that the USB interface is just a USB to TTL serial converter chip. To eliminate the wired connection to the PC I modified my generator to install a Bluetooth to serial adapter. Specifically, I used a JY-MCU Bluetooth board that are sold for use with Arduinos. They are inexpensive and readily available from ebay and other sources. I bought mine from DX.com:
(http://www.dxsoul.com/product/jy-mcu-arduino-bluetooth-wireless-serial-port-module-901104299?utm_source=dxsoul&utm_medium=edm&utm_campaign=20141028GEEKdxsoul#.V1wXoMUeRv8 (http://www.dxsoul.com/product/jy-mcu-arduino-bluetooth-wireless-serial-port-module-901104299?utm_source=dxsoul&utm_medium=edm&utm_campaign=20141028GEEKdxsoul#.V1wXoMUeRv8)).
I installed it with a toggle switch between the generator and the Bluetooth module, builtin the USB interface so that I could switch between the two. Using a serial program like Putty or writing my own programs in Python I was able to wirelessly talk to the FY3200 over the Bluetooth COM6 virtual serial port. It worked great. Unfortunately, the Feelttech PC software would never connect over the Bluetooth virtual COM6 port. The software works perfectly over the USB virtual COM3 port.
Now, my questions for the forum.
1. Any suggestions on how to get the Feeltech PC software to work with the Bluetooth COM port??
2. I have one of the older FY3206S generators from summer 2015 that powers up saying ver 1.2. My Feeltech software was installed from a version labeled FY3200PC SoftwareV1.3.exe. Is there a newer version of the Feeltech software that people find works with the original ver 1.2 unit? I would like to try a newer version to see if I can get it working over my Bluetooth wireless mod.
gby
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gby, that's a very cool idea to slip in a TTL-to-Bluetooth interface. I'm not sure why the FeelTech software won't work with it. Perhaps it's not happy with the higher COM number, though that seems a silly limitation if it is the problem. Are you able to force the Bluetooth interface on the computer down to COM3 or the USB interface up to COM6 to see if it makes any difference?
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I think it should be fairly easy to write an Android application that uses Bluetooth to interface with the FeelTech signal generator.
Another alternative is to use the FT311D or FT312D chip from FTDI that provides a USB host to your Android phone or tablet device, based on the Android Open Accessory mode that is supported since Android version 3.1 and onwards.
As there is enough space available in the FeelTech signal generator, you could even build in the FT311D Evaluation Board, and make the USB port available on the outside of the device.
http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342 (http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342)
This would provide Android support to your FeelTech signal generator.
It would highly increase the value of your signal generator!
Here is a nice tutorial from DigiKey about Android Interface Solutions:
http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html (http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html)
Enjoy!
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Thanks for your detailed message, Gby.
I'm a informatic (and english speaker) dummy, but I'm going to try. I will comment the results.
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I installed it with a toggle switch between the generator and the Bluetooth module, builtin the USB interface so that I could switch between the two. Using a serial program like Putty or writing my own programs in Python I was able to wirelessly talk to the FY3200 over the Bluetooth COM6 virtual serial port. It worked great. Unfortunately, the Feelttech PC software would never connect over the Bluetooth virtual COM6 port. The software works perfectly over the USB virtual COM3 port.
I'll try using an FTDI converter in place of the CH converter to see if the software works with that - I'd be surprised if they are looking at any serial numbers or enumeration of any particular device.
Another thing to try would be to download some serial port sniffer software to see if they're doing anything special which the Bluetooth converter doesn't support. :-//
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Stevey's got another vid update: cool ventilation mod, USB isolation, tinkering with the PC software:
https://www.youtube.com/watch?v=HqF_1y3U_qg (https://www.youtube.com/watch?v=HqF_1y3U_qg)
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The FeelTech FY3224S is a bench type signal generator.
FeelTech also produces a portable non-bench type signal generator with a colour screen, the FeelTech FY2300:
http://en.feeltech.net/html/Signal%20generator/show_17.html (http://en.feeltech.net/html/Signal%20generator/show_17.html)
I wanted to point out here that FeelTech has recently released an improved version of their portable non-bench type signal generator, the FeelTech FY2300H:
14-bit D/A converter, 250 MSa/s sample rate, 8 Mpoints sample memory, 0.1 deg phase resolution
Improved power supply design to reduce noise on the signal output
http://en.feeltech.net/html/dynamics/show_49.html (http://en.feeltech.net/html/dynamics/show_49.html)
Personally I like the FeelTech FY3224S bench type signal generator better, as it better suited for a lab environment.
Maybe they will release a FeelTech FY3224H as well in the future :)
That's why I wanted to share more info about the non-bench type signal generator in this thread.
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Here is my solution to reduce residual voltage and leakage current:
(https://abload.de/img/p1300961-6x4usph3.jpg) (http://abload.de/image.php?img=p1300961-6x4usph3.jpg)
Not as perfect as Steve's solution, but simler, cheaper, faster. And does not need a fan.
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Looks nice. Some info about the used parts and sources (Conrad? eBay?) and a circuit diagram would be helpful.
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Thanks. Posts Reply #296 and Reply #289 give some options.
At the end of the day I used
- 2 pieces PRINTTRAFO (PCB Transformer) Gerth 2X30V 5,6VA #V050561 @ Voelkner.de (cheaper (5,47 EUR each) and I have shipping flat rate) or Conrad 1092928 - 62 ; EAN: 2050001920652
- 1 veroboard Epoxy PCB with dots (off the shelf)
- 1 fuse holder (off the shelf)
- some cables 0.5mm^2 230V approved
- 2 pieces cut of a threaded rod 3mm
- some plastic sleeves or hoses to isolate the rods and to give them a similar diameter as the posts
- some cable ties to fix the PCB to the rods
- some heat shrink
- some hot melt
Doing:
- solder the Transformers on the PCB
- remove copper dots around 230V pins to get a clearance of ca. 10mm
- connect primaries in parallel
- connect all 4 secondaries in series and connect to the input of the original swiching power supply
- remove the 2 cables of the on/off switch and short them together
- connect the primaries over the switch and the fuse to the mains inlet jack
- heatshrink the HV cables
- tap M3 threads into the 2 bottom plastic posts
- enlarge the holes of the 2 top plastic posts to 3mm or 3.5mm
- srew the threaded rods into the lower posts
- remove back plane fiddle all togehteher (the rods in the holes of the upper posts) and fix the PCBs to the rods using cable ties
- fix the rods to the PCB a little bit so the the direction of the rod is fixed and will meet the top stands during final assembly
- put backplane back and do final assembly
I am not sure if it is really worth while drawing a circuit diagram, up to now I did not.
I use no fan. The hottest temp I measured is between the two transformers and is 48°C. You can increase the distance between the two transformers to 5 or 10mm to reduce this temp a few degrees.
Edit: Schematics added
(https://abload.de/img/feeltech-transformersjauue.jpg) (http://abload.de/image.php?img=feeltech-transformersjauue.jpg)
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Edit: Schematics added
(https://abload.de/img/feeltech-transformersjauue.jpg) (http://abload.de/image.php?img=feeltech-transformersjauue.jpg)
That's actually a great solution - much simpler and just as effective! :-+ :-+
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much simpler
Thank you! Simpler and cheaper - I agree.
and just as effective!
Im am not sure because so I have to rely on the properties of the original switched mode power supply. And frankly spoken, I never measured this quality (e.g. ripple). Your solution delivers a very controlled high quality supply voltage.
Maybe I am spoiled by my daily job. So I could not overcome myself to invest that money and time in a 60EUR device even it is woth while doing. Sorry.
Currently I measure ca. 20V and some µA between GND and protection eart. So it is not as good as your solution but hopefully good enough for my purpose.
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Thank you. Very good description and surely enough to "fix" the device with lowest costs and effort. A small inside isolation transformator. I am currently using a "little" bigger 1000VA isolation transformator for this on my bench but this is really not a very mobile solution ;-). So your modification would be my best guess for this device if I ever need to be mobile with the F"l"eeTech ;-). Thanks again!
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Thank you!
I also have an older chunky 630VA safety isolation transformer under my bench. It is a potted green monster, has an inrush current limiter and a grasp on top for better mobility :)
But normally I do not use it for my test gear but more for the DUTs.
So I was willing to spend 11EUR and some spare time for the FY3224S.
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I've received my fy3224s and after some some search seem that the output amplifier is this one:
http://pdf.datasheetcatalog.com/datasheets/700/322243_DS.pdf (http://pdf.datasheetcatalog.com/datasheets/700/322243_DS.pdf)
Maybe can find a drop in alternative with more power...
I can confirm low +/-12v output on his psu. With 5.24v on the 5v line there are less than 11v on the +/-12v lines.
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Ordered 2 of this:
http://www.ti.com/lit/ds/symlink/ths3092.pdf (http://www.ti.com/lit/ds/symlink/ths3092.pdf)
For the output buffer, must provide enough power. The other parameters are similar to the original THS3002 (slew rate only a bit slower).
First of all need to sort the poewr supply...
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Gby:
I have managed record two waveformes in the pos ARB1 and ARB2: 8 & 10 senoidal cicles. At high frecuencys, time and phase jitter appear. Amplitude fall -logical- but it's still useful. In RF RX adjusts, level required is low but precission and stability is critically.
Thanks
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Ordered 2 of this:
http://www.ti.com/lit/ds/symlink/ths3092.pdf (http://www.ti.com/lit/ds/symlink/ths3092.pdf)
For the output buffer, must provide enough power. The other parameters are similar to the original THS3002 (slew rate only a bit slower).
First of all need to sort the poewr supply...
Interesting idea. I'm trying to figure out which performance spec (or specs) this would improve on the function generator. I looked at the data sheets you quoted. Seems the biggest improvement of the THS3092 over the THS3002 it is ability to source 250ma vs 100ma. Are you thinking with the THS3092 you could drive larger voltage swings past 6MHz where this generator starts attenuating the amplitude and starts rounding off every waveform shape into a sine wave?
Mean-Well PD-2512 or PD-2515 might be good power supplies. Although they don't do +5v for the digital, they would supply sufficient "analog" drive current, and are reasonably priced.
Please let us know your thoughts.
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Add a regulator or buck converter to get the +5.
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Add a regulator or buck converter to get the +5.
This is my plan. I've ordered an LM317/LM337 linear regulator board to generate the +12 and -12V lines, and then I was just going to tap from the pre-regulated 16-ishV output from the bridge rec. of that board into a 5V buck regulator of the LM2597 variety. See also
https://www.eevblog.com/forum/testgear/feeltech-fy3200-psu-upgrade/ (https://www.eevblog.com/forum/testgear/feeltech-fy3200-psu-upgrade/)
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Currently there is too much focus on the improvement of the power supply IMO.
When are we going to tackle the signal output instead? :)
What about the other improvements, like improving the quality of the signal output?
Power circuit as such, is a NICE to have improvement, but further improving the signal output is more MUST have :)
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Anyone here who played around with the improved 14-bit D/A version?
The FeelTech FY3224S is a bench type signal generator.
FeelTech also produces a portable non-bench type signal generator with a colour screen, the FeelTech FY2300:
http://en.feeltech.net/html/Signal%20generator/show_17.html (http://en.feeltech.net/html/Signal%20generator/show_17.html)
I wanted to point out here that FeelTech has recently released an improved version of their portable non-bench type signal generator, the FeelTech FY2300H:
14-bit D/A converter, 250 MSa/s sample rate, 8 Mpoints sample memory, 0.1 deg phase resolution
Improved power supply design to reduce noise on the signal output
http://en.feeltech.net/html/dynamics/show_49.html (http://en.feeltech.net/html/dynamics/show_49.html)
Personally I like the FeelTech FY3224S bench type signal generator better, as it better suited for a lab environment.
Maybe they will release a FeelTech FY3224H as well in the future :)
That's why I wanted to share more info about the non-bench type signal generator in this thread.
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Who is going to add Android support to this signal generator, based on the FT311D or FT312D chip?
I think it should be fairly easy to write an Android application that uses Bluetooth to interface with the FeelTech signal generator.
Another alternative is to use the FT311D or FT312D chip from FTDI that provides a USB host to your Android phone or tablet device, based on the Android Open Accessory mode that is supported since Android version 3.1 and onwards.
As there is enough space available in the FeelTech signal generator, you could even build in the FT311D Evaluation Board, and make the USB port available on the outside of the device.
http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342 (http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342)
This would provide Android support to your FeelTech signal generator.
It would highly increase the value of your signal generator!
Here is a nice tutorial from DigiKey about Android Interface Solutions:
http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html (http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html)
Enjoy!
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Currently there is too much focus on the improvement of the power supply IMO.
When are we going to tackle the signal output instead? :)
Once I have a power supply I actually feel safe around, that'll be next on my list.
(I'm planning to fully-encapsulate the mains side of the input/transformer circuitry, thus leaving no exposed mains inside the case while it's open)
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i'm waiting the THS3092D for try to improve the signal output....
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Who is going to add Android support to this signal generator, based on the FT311D or FT312D chip?
I think it should be fairly easy to write an Android application that uses Bluetooth to interface with the FeelTech signal generator.
Another alternative is to use the FT311D or FT312D chip from FTDI that provides a USB host to your Android phone or tablet device, based on the Android Open Accessory mode that is supported since Android version 3.1 and onwards.
As there is enough space available in the FeelTech signal generator, you could even build in the FT311D Evaluation Board, and make the USB port available on the outside of the device.
http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342 (http://www.digikey.com/catalog/en/partgroup/ft311d-evaluation-board-umft311ev/33342)
This would provide Android support to your FeelTech signal generator.
It would highly increase the value of your signal generator!
Here is a nice tutorial from DigiKey about Android Interface Solutions:
http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html (http://dkc1.digikey.com/us/en/TOD/FTDI/Android-Interface-Solutions/Android-Interface-Solutions.html)
Enjoy!
You have a lot of requests of other people.
My question to you is what are YOU doing?
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I am suggesting the new ideas here! :)
As the original poster of this thread, I do believe that I have the freedom of suggesting new ideas =)
And yes, I want to help out as well, but unfortunately not in a position right now, because of time constraints. Hopefully this will change in the future, so that I can be part of active contributions.
Note that I was in contact with FeelTech about the reported issues in the past, and I actually got hold of them once, where they even confirmed that they will put one of their engineers on it. But afterwards, there was no feedback anymore from them. Really hard to understand, why they don't see any need for further improving their product. If they only would strengthen themselves a bit more, the product could become so much better, without much additional cost. But it seems like Chinese companies simply don't think like this. Obviously every penny counts for them, but I think in this case, it is not related to pennies, but more related to an attitude problem. They just think that whatever they do, is good enough, and that there is no need to strengthen any further. This gives me the impression that they operate under a "we know, but don't care" policy! Unfortunately there are many Chinese companies out there that seem to operate under this policy. With that said, I think that we can forget about any actual support from FeelTech, at least in the near future. We will have to come up with our own solutions to further improve and perfectionize their products! :)
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Note that I was in contact with FeelTech about the reported issues in the past, and I actually got hold of them once, where they even confirmed that they will put one of their engineers on it. But afterwards, there was no feedback anymore from them. Really hard to understand, why they don't see any need for further improving their product. If they only would strengthen themselves a bit more, the product could become so much better, without much additional cost. But it seems like Chinese companies simply don't think like this. Obviously every penny counts for them, but I think in this case, it is not related to pennies, but more related to an attitude problem. They just think that whatever they do, is good enough, and that there is no need to strengthen any further. This gives me the impression that they operate under a "we know, but don't care" policy! Unfortunately there are many Chinese companies out there that seem to operate under this policy. With that said, I think that we can forget about any actual support from FeelTech, at least in the near future. We will have to come up with our own solutions to further improve and perfectionize their products! :)
That is a bit unfair - do you know their cost of production? Do you know if they get components at discount, or if they are still in the red to recoup design expenses?
Improving cheap stuff has been around the audio "phool" or "engineering" area for at least 30 years. Nowhere were the compromises made by engineering frowned upon. The senseless compromises (e.g. what is available behind the fish monger in Shenzen) enabled the cheap price and eventual progression towards acceptable products.
Eventually their resources invested in this line will clear the black (hopefully) and at that point resources may be freed up and the design may be improved.
(on a side note: If you were the owner - wouldn't you wait for the hobbyists to come up with a stable solution - and then just copy it? - seems all the maker stuff like 3d printer controllers evolve like this...)
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Engl. soft V2.2 + manual 2016MAY11
http://en.feeltech.net/index.php?case=attachment&act=down&aid=47 (http://en.feeltech.net/index.php?case=attachment&act=down&aid=47)
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Note that I was in contact with FeelTech about the reported issues in the past, and I actually got hold of them once, where they even confirmed that they will put one of their engineers on it. But afterwards, there was no feedback anymore from them. Really hard to understand, why they don't see any need for further improving their product. If they only would strengthen themselves a bit more, the product could become so much better, without much additional cost. But it seems like Chinese companies simply don't think like this. Obviously every penny counts for them, but I think in this case, it is not related to pennies, but more related to an attitude problem. They just think that whatever they do, is good enough, and that there is no need to strengthen any further. This gives me the impression that they operate under a "we know, but don't care" policy! Unfortunately there are many Chinese companies out there that seem to operate under this policy. With that said, I think that we can forget about any actual support from FeelTech, at least in the near future. We will have to come up with our own solutions to further improve and perfectionize their products! :)
That is a bit unfair - do you know their cost of production? Do you know if they get components at discount, or if they are still in the red to recoup design expenses?
Improving cheap stuff has been around the audio "phool" or "engineering" area for at least 30 years. Nowhere were the compromises made by engineering frowned upon. The senseless compromises (e.g. what is available behind the fish monger in Shenzen) enabled the cheap price and eventual progression towards acceptable products.
Eventually their resources invested in this line will clear the black (hopefully) and at that point resources may be freed up and the design may be improved.
(on a side note: If you were the owner - wouldn't you wait for the hobbyists to come up with a stable solution - and then just copy it? - seems all the maker stuff like 3d printer controllers evolve like this...)
The engineers that offered suggestions normally have good intentions and assume that it is very profitable business for the makers in China. The seller knew about the good intentions but did not explain their difficulties due to many reasons: 1. Do not want to offend people with good intentions 2. Respect 3. Language barrier 4. How and what is the point of making outsiders understand their situations and problems.
The biggest problem the shop that came out with a product that start to sell is the invitations to many other copiers that jump on them almost immediately. The competition is against the copiers that are using savaged parts and hardly making minimum wage while loaded with debts. The eco system does not allow them to fulfill the request. They know that. But the requester probably did not know that most of the answers are just for courtesy and are for PR. And the requsters definitely do not know that fulfilling the request shall mean a definite death to the seller operation and cash flow. If they can come out that product, they have some minimum intelligent to know something. And the ignorant party maybe someone else.
So it amaze to see people here trying to save on an already cheap universal programmer MiniPro .
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......serial port connector J4 lists the pin out on the silk screen as:
5V
GND
TXD
RXD
Depending on whether you name the signals for the device (DTE) or where they go (DCE) TXD might be the generator output or the input. So, do you know if pin 3 labeled TXD is driven by the FY3200 generator or if it listens on that pin?
Second question, are the signals on these lines 3.3V level or 5V level?
I hooked up my scope to the USB to Serial card T pin on J2. That wire goes to the front panel J4 pin RXD. Then I change setting in the FY3200S v2.0 software. My scope measured 5volts on that pin. I got nothing on the TXD pin from J4. It looks like TXD driving and RXD is listening at 5 volts.
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I decided to go with the DIY on-board isolation transformer solution as well but in a primary - secondary - secondary - primary configuration. Hardly any voltage drop or heat generation so the surgery seems to be a success. Also added a IEC male socket, fuse holder and a mains earth switch. Switched on I get about ~17V between device ground and mains earth, turned off a couple. Its a basic 2Mhz model and came with firmware revision 3. Apart from SIN, SQR, and TRI it has RAMP, NRAMP, PULSE, 4-PULSE, 8-PULSE, STEP and DC selectable wave forms. There's a FOLLOWING option in MENU which let's you select AMPL, OFFS, DUTY and FREQ for CH1=CH2. Have to work out what this does exactly, the manual is for an older version without this option. A big thanks to Classical for the isolation suggestion.
Cheers,
John
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I decided to go with the DIY on-board isolation transformer solution as well but in a primary - secondary - secondary - primary configuration. Hardly any voltage drop or heat generation so the surgery seems to be a success. Also added a IEC male socket, fuse holder and a mains earth switch. Switched on I get about ~17V between device ground and mains earth, turned off a couple. Its a basic 2Mhz model and came with firmware revision 3. Apart from SIN, SQR, and TRI it has RAMP, NRAMP, PULSE, 4-PULSE, 8-PULSE, STEP and DC selectable wave forms. There's a FOLLOWING option in MENU which let's you select AMPL, OFFS, DUTY and FREQ for CH1=CH2. Have to work out what this does exactly, the manual is for an older version without this option. A big thanks to Classical for the isolation suggestion.
Cheers,
John
Good looking work.
The FOLLOWING option sounds exactly like the MHS- series (I have the MHS-5200A) TRACE (or TRACK). It basically makes CH1 and CH2 have equal properties (except the waveform itself). In your case, you can make Frequency, Amplitude, Phase, and Offset be equal.
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Has it been confirmed that the 2 MHz version is identical to the 24 MHz version in terms of hardware?
How to perform the software upgrade? :)
Is there a big difference in price between the entry model and the top of the line model?
Maybe it's not worth the trouble, if the prices are very similar anyhow.
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I've noticed from the photos that my 24mhz have the cooler over the opamps.
What opamps have the 2mhz version?
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Has it been confirmed that the 2 MHz version is identical to the 24 MHz version in terms of hardware?
At one point, it was noted that all speeds were the same hardware.
How to perform the software upgrade? :)
An earlier firmware revision could be upgraded. That "feature" has since been eliminated.
Is there a big difference in price between the entry model and the top of the line model?
Maybe it's not worth the trouble, if the prices are very similar anyhow.
The last time I checked, the price difference between models was OK. However, that interpretation is subject to where each person draws the line between time and money. I don't know if there even is a way to upgrade it now, anyway.
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I have been wondering about that upgrade feature. From a production point of view it makes sense to have it included in the firmware as a way to quickly differentiate products. So in other words the feature may not have been eliminated but following a different coding scheme.
I take it the firmware is safely locked away from user view?
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As I recall, the bug/loophole/method that was used to switch the maximum frequency was fixed so that it could not be exploited anymore.
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Has it been confirmed that the 2 MHz version is identical to the 24 MHz version in terms of hardware?
How to perform the software upgrade? :)
Is there a big difference in price between the entry model and the top of the line model?
Maybe it's not worth the trouble, if the prices are very similar anyhow.
Since you are in communication with the OEM, why don't you ask them and also ask why are they not performing the improvement you have asked.
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I contacted them already 2 times, without any response whatsoever.
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I've ended the build of the linear psu and tried to change the opamp (THS 3002) with a more powerful one (THS 3092), and i've traced the circuits around the opamp.
On the "IMG_20160731_190120.jpg" attachments you can see the schematic Of the CH1 with some components identified.
The output of the 12 bit R-2R if fed on a filter (LL2 1.2uH, C39 4pF, LL4 800nH, C43 8.6pF), then directly on the output opamp. The W6 trimmer adjust the gain of the output.
Then i've not fully understood what do the second opamp in the THS3002. Is fed directly by a second 12bit R-2R, then enter in an analog mux (the 'common' input of an hc4053). The non inverting input is 'adjusted' by W3. Maybe one do the positive part of the wave and the other one the negative, and the switch is done with the analog mux? There are in total 8 anaog mux (4 per channel)...
The 4558 sets the offset, seem that the mcu fed it via a pwm signal, filtered by C54/R108 and C55/R109. W4 i think that adjust manually the offset.
The change from the THS3002 to the 3092 gave me some strange results... I've tested it with 50 ohm termination. The waves don't reduce anymore amplitude increasing the frequency (image "8mhz 20vpp.png"), but i've got some nasty oscillations and overshots (image "4mhz 10vpp.png" and "8mhz 10vpp.png"), that maybe can be cancelled with some tweaks. The signal rise/fall a bit faster and the edges are a bit better. With this opamp there is the need of a bigger cooler as it heats quite fast.
Some thoughts?
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Noticed also that the r/2r network is done with 01B (1k 1%) resistors and 68A (499 ohm 1%) resistors, so the voltage divider created by the r-2r have a little error... Maybe using 2 1k resistor in parallel in place of the 499 one can increase a bit the accuracy, and also doing some "matching" for the resistors can increase the precision... Actually measuring them with a precise ohmmeter i get constantly a bit less than 1k... Not know how this reflect with the accuracy.
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deleted..
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Im sorry, this question some different your generator model :(... a FY2300 6mhz..
FY2300 thread (https://www.eevblog.com/forum/testgear/software-and-manual-for-feeltech-fy2300/msg962101/#msg962101) ;)
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thank you
Im re-write correct post
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@Classical: this solution doesn't solve potential issues with noise from the AC power supply being pushed into your circuit. The best and easiest thing to do is to ground it.
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@Classical: this solution doesn't solve potential issues with noise from the AC power supply...
Yes, you are right and I am aware of that. But it reduces the leakage current and residual voltage enough for most of my applicactions.
And I am also aware that the solution of JBourke has the potential to reduce capacitive coupling about 4 times better than my solution. But that doubles the volume and cost if you do not the appropriate transformers on stock anyway.
In general I try to avoid PE on my measiring equipment but of course there are also temporary exceptions which can be wired easily if necessary.
Many years ago I had to deal with fA and I experienced the benefits of active shielding and battery powered equipment.
But for my hobby purpose and tinkering I have to find an appropriate compromise.
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I've tryied to understand what was the purpose of the analog switches, and seem that the first 12bit r-2r network (24 resistors, R38-R48+R100, R85-R96) if fed via the analog switches, that switch every bit from ground to a negative voltage set by W3 via the second opamp of the output amplifier (see schematics of my previous post). The second r-2r network is fed directly by the altera cyclone FPGA (switch from 0 to +5v of vcc).
So actually there are 2x 12 bit R-2R DAC, for a total of 48 resistors and 24 bit for a full wave. Why the resolution is only 12bit? Maybe for user waveform is 12 bit and for example for a sine wave it's full 24-bit?
I've not understood why using a more powerful output opamp i've got oscillations on a square wave (as previous post)...
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With futher analysis i've undestood that the signal is generated by the r-2r network directly connected to the altera FPGA (so i get a 12bit 3.3v wave), then goes in the second opamp of the THS chip, got amplified and have the right negative bias, then enter in the analog mux and second r-2r, that attenuates it (via the amplitude setting). Then goes to the LC filter, and finally got amplified on the first opamp in the THS chip for the output. The offset is set by a pwm output on the FPGA that goes in a rc filter for DAC conversion, the get amplified by the 4558 opamp.
Probably i get worst response on square wave with the more powerful THS3092 because with the sharper edges (faster rise/fall times) the filter does not work well, next thing is to try to simulate the filter and try to get it work better with the more powerful output opamp. I've also changed the resistors with some 0.1% 25ppm precision resistors (all 1k, i get the r value paralleling 2 resistors). Now i have a more precise and linear output (but i still have some non linear response as i can't set perfectly the voltage output that matches the setting over the wole 0-20vpp amplitude)
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masterx81, thanks for continuing to share your findings. Has the change to precision resistors fixed the anomaly in the waveform near the zero-crossing that was attributed to the R-2R ladder?
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg930730/ (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg930730/)
(https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/?action=dlattach;attach=221310;image)
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With 2.3khz setting and 5v amplitude triangular wave like your test (not using 50 ohm termination, scope probe directly on output connector), i still get a 12mv "jump" between the 2 waveforms, that's the same that i have with the untouched CH2 channel.
I was expecting to have that error almost erased using precision resistors...
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Same test conditions, 50 ohm termination, 5mv div
RED is CH1 modified (also with THS3092, so the overshot caused by the filter), YELLOW is CH2 unmodified
(Sorry for my noisy OWON scope :( I have also an old hameg analog scope but for this owon was sufficient)
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What if you make a custom wave that is all positive, and then use offset to center it? Obviously you lose half the amplitude, but perhaps fix this crossover issue? Or is the offset before the "DAC" ?
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I've also tryied to upload a custom triangular waveform with 0 4 8 ... 4092 4095 4091 ... 11 7 3 sequence (with the upload software, preset waveforms) so that i'm sure that in the middle of the waveform there isn't any interruption (as the conjunction is between the 0 of the start and the 3 of the end of the waveform, so near -V and not around 0v) and it do the same thing.
The error is already present at the output of the first opamp (the one that "center" the waveform so that the 2047 digital output of the r-2r match with 0v).
Maybe i can try to scope the direct output of the r-2r but i need to desolder the opamp (with the opamp in place the output of the r-2r is so small that i can't neither scope it, as it enters directly on the negative input of the opamp and the feedback resistor attenuate it, it's something like 2mvpp) but i have no time now for this, the only thing that i've done is to scope the 11bit node of the r-2r (that's not attenuated) and the error is already here. I not know why there is this imprecision around the 2047 but i suspect a firmware bug on the FPGA. I not know anything about FPGA (know only about MCU) so are only supposition...
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Thanks for checking the output with your mod. Bummer that it didn't fix it. I was hopeful.
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Hi, what is the lastest version of the PC software? And firmware?
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I'm using the sw version 1.4 (as the 2.0 seem only in chinese), and firmware/revision 2.0.
In my linear psu i've changed the 5v stabilizer from 7805 to a little smps module pin to pin compatible with the 78xx, and i have so much less heat on the heatsink... The only negative part is that the +5v rail feed also the +v of the analog switches (the -v is produced with a negative linear regulator on the board that is fed with -12v), but the ripple of few 10 mv is not giving any problem as after the first opamp the signal is near 7vpp.
I'm trying also to linearize the output so that the voltage set is the same that i get. For the offset i've replaced the R113 (3k9) with a 5k multiturn pot for have the correct amplification of the offset signal.
For testing the signal output i've uploaded 3 waveforms, one of all 0's (so i get a negative half of the amplitude setting), one of all 2047's (so that i have a plan 0v output - like setting the frequency to 0hz) and the last one of all 4095 (so i get a positive half of the amplitude setting). In theory all stages works in a linear way (the first amplification is linear via the opamp, then there is the attenuation via r/2r with precision resistors that must be quite precise and linear, and the last is the power opamp), but if i adjust the amplitude that matches with 10vpp setting it not matches with 20vpp, need to investigate a bit more.
The filter used to smooth the waveform seem an elliptic one, with capacitors to ground removed. Tried to simulate it but got notinhg usable. I will try a bessel one as soon as arrive a kit of 0603 inductors/capacitors...
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latest software version 2.2 + manual + communication protocol spec ; 2016MAY11
http://en.feeltech.net/index.php?case=attachment&act=down&aid=47 (http://en.feeltech.net/index.php?case=attachment&act=down&aid=47)
CH 340 USB drivers
http://en.feeltech.net/index.php?case=attachment&act=down&aid=25 (http://en.feeltech.net/index.php?case=attachment&act=down&aid=25)
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Thanks for the link of the new sw! Seem identical to the other one that i had (1.4)...
I've tried to find where are the non-linearities in the amplitude, and are in the 4053 analog switches used for attenuate the signal amplified by the first opamp... i've bypassed the final amplification stage and the filter (for unloading the r-2r attenuation network), set a constant voltage out of the the dac, then set the amplification setting to 20v (maximum, so that all the analog switches was selecting the input signal - so no attenuation), measured the voltage in input of the analog switches and at the output (at the resistors), and at the output the voltage is not the same as the input. Nice to notiche that some only some chip are out of spec (as much as 1% error), so with a good selection of 4053 is possible to select the most precise one's and use them (thig that i'll do as they are quite cheap)
Got it: The error is due to the on resistance of the analog switches. I've cheked and seem that all the 4053 from various makers have almost the same specs. How much is bad paralleling 2 analog switches? Or eventually change the r2r from 500ohm/1k to 1k/2k?
Also the ADG733 is an interesting alternative, the low on resistance will eliminate the problem. But need to convert supply from +/-5v to +3.3v/-2.5v, not too complicated but then there is the need to reduce the amplification of the first opamp (that amplify the signal up to 7vpp) to max 5vpp.
I was not able to find an analog switch with same voltage rating and lower on resistance other than this... Also valuated to use an unity gain buffer but i not think that's a good solution.
Found also what's causing the error at around half of the 12bit scale, it's the switch of the msb. The problem (at least, this one) isn't the precision of the resistors, but that around the lsb the load on the altera chip caused by 500/1k resistor is too much and the output of the chip is not 3.3v but a bit less (Also here, due to on resistance). Need to try to switch from 500/1k to 1k/2k, or 5k/10k or 10k/20k. I not know if this have negative sides, but for sure change the impedance of the network, increase noise and increase error due to input bias current of the opamp.
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@masterx81: The impact of the various on resistances makes a lot of sense. Interesting what you found about the loading on the Altera. Hopefully, resistor values can be found that will yield a happy medium between load and noise.
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Yes, it's a tradeoff...
I think that on dac side i'll go with the increased value resistors way. If i want to reduce the opamp error a second opamp can be added, with low bias current. In this way we free the second opamp of the THS3002 chip, allowing to put in parallel the two opamp and get more output current without changing it with the more powerful THS3092 (paralleling them in this way: https://e2e.ti.com/blogs_/archives/b/thesignal/archive/2013/03/26/paralleling-op-amps-is-it-possible , as a normal parallel need 2 pot for setting amplification the same on both amps). For the attenuation side i think that the best thing to do is use the adg733 analog muxes. Need to try to find them cheap. After all this remain to tune the output filter.
I think that with this mods the device will be quite accurate...
Also the ADG1433 with 4ohm Ron is nice, but it's not pin to pin compatible with the 4053...
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Sounds like a good recipe. You've become quite the guru on this generator! Looking forward to seeing your new-and-improved version (Masterx8124S ^-^).
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A guru is someone that already know what's doing, i'm only learning and doing tests to made this product a bit better without spending too much. A good function generator costs too much for me, and i prefer to increase my knowhow a bit...
Someone with good skills can do all this in few minutes :(
In the meantime i was searching other triple analog muxes with ron<5ohm, and the only ones seem adg1633, adg1433 (almost identical, with different bandwidth) and the pin to pin compatible adg733. The first two have 4ohm Ron, the supply can be unchanged (works with +5/-5v), but the pinout is a lot different, and not seem pratical the conversion.
The adg733 is almost compatible, but it have a suggested supply of +2.5/-2.5v. This is not good as the control lines from the altera chip are 3.3v and the digital lines allow a maximum of vcc+0.3v (so 2.8v), so at least the +v must be +3.0v (but we have already a 3.3v regulator so i'm using it), giving a total voltage of 5.8v, a bit out the reccomended 5.5v max but a lot less than the absolute maximum limit of 7v.
The things to do for have it working in the signal generator is lift the +vcc pin and connect it to the +3.3 voltage regulator (including coupling capacitor), change the onboard -5v voltage regulator to a -2.5v one (the -5v seem used only by the analog switches), change the feedback resistor of the opamp after the dac for have a max 5vpp (better a bit less) signal instead of the near original 7.5vpp, and change the gain of the power output opamp. the 2.5ohm ron resistance of the adg733 vs the 50~80ohm ron of the 4053 will increase a lot the accuracy of the amplitude setting. if it's not enough, it's possible to increase the value of the r-2r attenuation network.
The big question about all this mods is the output filter, i not know almost nothing about filter design |O Plus at least one hundred of things that for sure i'm missing as i have no experience in this field... But i want to learn :P
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Upgrade of FY3224S(opamp THS3002): linear psu and the amplifier on 1 channel from opamp LT1210CT7.
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Upgrade of FY3224S(opamp THS3002): linear psu and the amplifier on 1 channel from opamp LT1210CT7.
Interesting, did you have scope traces of ch1 vs ch2 at various frequencies?
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Interesting, did you have scope traces of ch1 vs ch2 at various frequencies?
Ch1(out1 LT1210) vs ch2(out1 THS3002), amplitude on the generator 10V:
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Thanks!
Have you placed the LT1210 as a buffer after the ths3002 or you have bypassed and substituted the output opamp? As seem that the ths3002 is present (for amplificating the signal after the DAC)
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Thanks!
Have you placed the LT1210 as a buffer after the ths3002 or you have bypassed and substituted the output opamp? As seem that the ths3002 is present (for amplificating the signal after the DAC)
I did this scheme, LT1210 as AV=2 after a resistive divider 1:2 that after ths3002(50 Ohm out)
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Good for have only the benefit of higher current without have to recalibrate the output filter as i have to do... But the high slew rate of the ths3092 that i'm using extend a bit the frequency range of the square wave (you can see that the edges on my scope traces are more "steep" than the untouched channel), and the 260ma seem enough for not have attenuation at higher frequencies.
As soon arrive all the components i'll update my research....
Thanks for sharing!
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I too wanted to establish in the beginning ths3092 instead of ths3002, but is more optimum (more powerfully several times) for my tasks there was LT1210.
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Yes, if you remove the 50ohm output resistors (actually 2x 100 in parallel) you can use all that output power, else with +/-10v output you get 200ma max (while the ths 3002 have only 100ma output)...in your schematics i see 1ohm output resistor so i think that you need to drive huge loads (and the psu was designed with that in mind)...
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Yes, if you remove the 50ohm output resistors (actually 2x 100 in parallel) you can use all that output power, else with +/-10v output you get 200ma max (while the ths 3002 have only 100ma output)...in your schematics i see 1ohm output resistor so i think that you need to drive huge loads (and the psu was designed with that in mind)...
Yes, capacitive load really big. For example comparing, the oscillogram 1 - THS3002 (a maximum load 6V amplitude), 2 - LT1210(7V amplitude on the generator). The upper channel - U, lower - I (via the resistor of 1 ohms).
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Upgrade of FY3224S(opamp THS3002): linear psu and the amplifier on 1 channel from opamp LT1210CT7.
Wow..... That's look great...
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Wow..... That's look great...
Thanks.
Heating of radiators under good loading in the closed case isn't higher than 46C(radiator LT1210/ 40C psu) at the room temperature 22C. For improvement of ventilation in the case I have made several cuts.
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Hi! I've done some other mods to the signal generator.
Added a 40x40 12v fan, temperature controlled via a tc648b controller ic at 30hz pwm (nice toy :) )
I've also changed the R-2R DAC resistors to 1k/2k 0.1% insted of 500/1k, no noticeable increase in noise, the output of the first opamp is near 3.3vpp (quite ok for the maximum 5vpp that i'll have to use with the adg733 mux, maybe i'll try to icrease it at 4/4.5v for reduce at minimum possible the amplification of the power output opamp).
The error at the change of the MSB is reduced by a lot (see attached image), and i think that it's a good tradeoff. Can be almost totally eliminated by increasing the R-2R values (next step with common resistor values is 5k/10k), but i not think that is the case as for me it's ok 1 or 2 bit step error.
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The use of 0.1 % resistors at 1:2 ratio does not help much with the R2R DAC. There is also the output resistance of the digital outputs that is effectively in series to the 2R resistors. So suitable resistors would be at something like 1 K and 1920-1980 Ohms depending on the Outputs. So 1 K and 499 Ohms was bad. 510 Ohms instead of the 499 would be likely the better solution.
Even worse the output impedance can be different for high and low state and temperature dependent.
To reduce the error one might need to adjust the resistor(s) at the most significant bit(s). As a pot will add too much capacitance this can get a little tricky. The 2 K resistors in series to the bit lines are slightly on the high side. So one could use a resistor and series pot to GND to reduce the amplitude of the lower bits contribution (connect where the last 1 K resistor meets the second last 2 K). Assuming about 30-50 Ohms for output resistance, something like a 27 K to 50 K resistor and a 10 K Pot could be about right.
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Yes, i know that using perfect 2:1 ratio isn't the best choice, in any case digital output On resistence differ from Off resistance, and change with temperature, so it's difficult to spot the right value. Also "strange" resistor values in 0.1% are not easy to find (and not cheap...). I'm trying to do the best as i can with cheap components...
Increasing from 499/1k to 1k/2k has made a better result (tested with oscilloscope) because with higher value resistor the On and Off resistance made less difference to the output network. Say on resistance of 2ohm on a 500ohm resistor is 0.4% error, 2ohm on a 1k resistor is only 0.2%.
For the impedance of the output, i'm not sure if made difference, as the output enter directly in the opamp (really high impedance).
In any case, thanks for the suggestion, as i'm not really confident with this type of circuits, and i'm learning playing with it...
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Hi Everyone,
Just received mine from Banggood today (26/10/2016) and thought I'd post some pics/version numbers as it may help someone. :)
Can't read the supplied cd, will try with another drive tomorrow.
Firmware version 3.5
Board version 2.1
Power Supply - still has leakage the same as other versions.
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The HW is the always the same, but they have updated the firmware... Would be interesting to see what changes they have made...
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Have they fixed the leading 0s yet, I can't stand strings of 0000s which look like 8888s to me.
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Wow, version 3.5. Mine is only 2.0. Is there a changelog somewhere? A quick search online wasn't fruitful.
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Have they fixed the leading 0s yet, I can't stand strings of 0000s which look like 8888s to me.
Not easy to fix/almost impossible.... And i bet that it's present on most 12bit signal generators. In any case the error is only few mv, and you can half it by using 1k/2k resistors instead of 499/1k.
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Changing the resistors to 1K/2K will only reduce influence of output impedance. With a maybe 20 Ohms output resistance they are still about 1% off. So only good for 6 to 7 Bits, not even 8 Bits. There is also a downside in going to higher impedance: parasitic capacitance gets more important and there can thus be larger glitches on switching.
So even 8 Bits only makes really sense if they go to more suitable resistors like about 510 Ohms instead of the 499 Ohms. As 510 ohms is a standard value chances are to find better values in newer units.The 510 Ohms / 1 K or 499 / 980 Ohms combination is likely better than the 1K/2 K pairs.
So instead of changing all the resistors, the more useful way would be adding suitable resistors (e.g. 50 K for a 20 Ohms driver resistance) in parallel to the 1 K ones for the more significant bits this way changing the 1 K to maybe 970-990 Ohms. The best value depends on the FPGA used and the actual value of the resistors. So it would take a few testes, possibly with temporary trimmers find the right value. Already changing the resistors for the 2 highest bits could be a significant improvement.
Getting true 12 Bit resolution is likely impossible even with well trimmed resistors, as the output impedance is quite temperature dependent and different for H and L state. Unless they have changed the resistor values, adding 4 more bits is not helping much.
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Have they fixed the leading 0s yet, I can't stand strings of 0000s which look like 8888s to me.
It's still the same.
I found this feedback on Banggood about the 3.5 firmware, I guess this is listed on the supplied cd. (My CD doesn't see to work need to try a different drive)
"The latest (v3.5) firmware has nice features - tone bursts (start & end cleanly on zero-crossing) - triggered by manual, external or channel 2, ASK & FSK modes (manual or external); 'manual' for these modes is the rotary encoder button. The counter can count pulses as well as measure input frequency"
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Thanks for the info on version 3.5, CCB. Sounds like fun stuff to tinker with. It'd be nice if they fixed the non-contiguous waveform during frequency changes.
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Hi community,
today my 3200S (24-MHz Version) arrived, but the cd can not be reed!
I want to download them from feel tech.net, but the website don't answer here in Germany.
Now, i need a driver & software packet to get them work on my PC.
Can every body send me a link to download them or has a information how to get?
Thank you very much.
PS: I download the manual from the website successfully but there is no DRIVER in it?
How to get the driver for Windows?!?
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Hi community,
today my 3200S (24-MHz Version) arrived, but the cd can not be reed!
I want to download them from feel tech.net, but the website don't answer here in Germany.
Now, i need a driver & software packet to get them work on my PC.
Can every body send me a link to download them or has a information how to get?
Thank you very much.
PS: I download the manual from the website successfully but there is no DRIVER in it?
How to get the driver for Windows?!?
As I may quote GigaJoe who posted this earlier in this thread:
latest software version 2.2 + manual + communication protocol spec ; 2016MAY11
http://en.feeltech.net/index.php?case=attachment&act=down&aid=47 (http://en.feeltech.net/index.php?case=attachment&act=down&aid=47)
CH 340 USB drivers
http://en.feeltech.net/index.php?case=attachment&act=down&aid=25 (http://en.feeltech.net/index.php?case=attachment&act=down&aid=25)
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Just ordered this little gizmo online, but I'm pretty sure it will arrive with firmware version 2.0.
Is there any way the user can update the firmware, or the one you get with the device is the one you are stuck with?
Well, whaddayaknow, it came with version 3.5.
My questions still stands, though, at least as a curiosity.
Also, I noted that the label on the bottom says: "o 12M x 24M o 25M". Mine is 24MHz.
Anybody has the 25 MHz version? What's the point of having 24 and 25 MHz versions?
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I also noticed that 25 MHz version on the newer units, but have not seen one marked as such. Why the extra 1 MHz? A guess is to match the competing MHS-5200 at 25 MHz.
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is it possible to calibrate the generator (by beating a 10, 15 MHz, etc. carrier against WWV ) Is there an adjustment pot or pad somewhere on the unit?
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Was planning on getting one of these to help me continue learning more about electronics. First thing on the list of MODs was the PSU improvement. Reply #325 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg964553/#msg964553 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg964553/#msg964553)) has a simple and inexpensive solution to the PSU concern to isolate the BNC ground from any other ground (or semi-ground as in the as-received unit). Since this floats the ground, would there be any issue with adding a switch to connect mains ground to the BNC ground as well? In that way the generator could have a floating ground or mains ground.
Also, one of the previous posts mentioned a USB isolator (http://www.ebay.com/itm/NEW-USB-Isolator-Magnetic-Coupling-Isolation-ADUM4160-USB-to-USB-/141998972441?hash=item210fcc5e19:g:aVAAAOSwEa5XPrRb (http://www.ebay.com/itm/NEW-USB-Isolator-Magnetic-Coupling-Isolation-ADUM4160-USB-to-USB-/141998972441?hash=item210fcc5e19:g:aVAAAOSwEa5XPrRb)) as well. Anyone tried this? Would be simple way to fully isolate the device, albeit between the USB isolator and PSU isolator would almost double the unit's price.
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is it possible to calibrate the generator (by beating a 10, 15 MHz, etc. carrier against WWV ) Is there an adjustment pot or pad somewhere on the unit?
No calibration that I'm aware of.
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Since this floats the ground, would there be any issue with adding a switch to connect mains ground to the BNC ground as well? In that way the generator could have a floating ground or mains ground.
Yes, it can and has been done. See reply #219 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg925053/#msg925053).
Also, one of the previous posts mentioned a USB isolator (http://www.ebay.com/itm/NEW-USB-Isolator-Magnetic-Coupling-Isolation-ADUM4160-USB-to-USB-/141998972441?hash=item210fcc5e19:g:aVAAAOSwEa5XPrRb (http://www.ebay.com/itm/NEW-USB-Isolator-Magnetic-Coupling-Isolation-ADUM4160-USB-to-USB-/141998972441?hash=item210fcc5e19:g:aVAAAOSwEa5XPrRb)) as well. Anyone tried this? Would be simple way to fully isolate the device, albeit between the USB isolator and PSU isolator would almost double the unit's price.
SteveyG added USB isolation among other mods in a series of videos. The USB isolator is covered in the video in reply #321 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg963737/#msg963737).
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Now there is discount with -15% off at banggood with coupon code "EMRLSP" for 3224s.
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Can anyone confirm that the new firmware does or does not have triggering for the sweep function, for the input of an oscope trigger
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Power Supply - still has leakage the same as other versions.
Interesting there is new power supply pcb board with input connectors on input. In mine FG they are directly soldered wires on input which is ugly. Now I have some improvements about earth grounding and leakage with upgraded input power socket.
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added 3wire power socket, but, instead short connection of central ground power wire and the device ground I use a 2.2mf 250V capacitor (110V wall power) voltage drop to 0.1V , did I made it right ?
still some noise at range 10-20 mV in the output signal, some 10-20 MHz
Hi everybody,
I also got one of these marvels. I wonder why GigaJoe in post #215 never got a suffucient answer (at least I found none) to the idea of using a capacitor between central ground power wire and the device ground. He measured a very small voltage of 0.1V between the 2 grounds, which should be harmless to any circuit the generator is attached to. And the outputs are still kind of "floating", aren't they? I am thinking about using a switch which selects A) a direct connection between central ground power wire and the device ground (the solution most people use) or B) the 2.2µF capacitor between central ground power wire and the device ground that GigaJoe has proposed.
BTW, I think it was a 2.2 µF =microFarad what he meant, not 2.2mf = milliFarad as he wrote.
My results, measured with an elderly Metex M-3640-D True RMS meter:
AC Voltage without Cap: 54.8V. With 2.2µF: 0.047V
AC Current without Cap: 785µA. With 2.2µF: 38 µA
Greetings,
mcmusic
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It's possible that GigaJoe's post was simply missed. Sorry, Joe.
Using a capacitor from the power connector's ground lead to the chassis ground will help reduce noise, but will not provide the same level of protection as connecting them directly. It's floating to a degree. So, it depends what your goals/requirements are. I supposed you could use a switch to be able to choose one of three configurations: grounded, filtered, floating.
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Would it be wrong to just connect siggen's socket to something grounded, like scope instead adding IEC socket and switch?
(http://imgur.com/a/VPQ73)
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The reason for grounding the device is to prevent the leakage from potentially blowing sensitive circuits. If you're connecting to something that doesn't mind the voltage levels, then there's no issue. But you'd have to remember that the potential is always there (pun intended, of course ^-^).
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Would it be wrong to just connect siggen's socket to something grounded, like scope instead adding IEC socket and switch?
ntoobe,
electrically this is sufficient (in the cases bitseeker described). However, I would not use it as this. Very easily one of the clips can come off.
You could use a less wiggly BNC cable and connect it between one of the often unused TTL-Outputs in the back of the 3224 and another grounded BNC connector.
Greetings,
mcmusic
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I have been looking to low cost freq Gen and was looking at both the Feetech FY3224s and the HM Instek HM5400 which are very similar to each other for price and Freq range. Initially was going with the Feeltech but after reading the leakage/power supply issues, not sure now. Any thoughts of which would be a better one to purchase.
Thanks,
RAD400
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It's such a good deal, relative to its competitors, though, and grounding it well through a three wire cord is easy, and eliminates the voltage issue.
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It's such a good deal, relative to its competitors, though, and grounding it well through a three wire cord is easy, and eliminates the voltage issue.
If it's that easy and cheap to solve the grounding issue, why does the Chinese manufacturer not do it themselves already in the factory? Stupidity and/or stubbornness?
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It's such a good deal, relative to its competitors, though, and grounding it well through a three wire cord is easy, and eliminates the voltage issue.
If it's that easy and cheap to solve the grounding issue, why does the Chinese manufacturer not do it themselves already in the factory? Stupidity and/or stubbornness?
They probably sell plenty without making the change. :-//
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Hi guys, just received my new FY3200 24MHz FG today and I've noticed that the frequency is off by approximately 5%. So, when the FG is set to 1k the hardware counter on my DSO reads 952Hz and at 10k it reads 9.52k. My DMM has a basic counter and it gives the same reading as the DSO. There's no offset; function=sine. Have I done something wrong? Is this a common problem?
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I should also have mentioned that the FGs own counter is also off by 5%. So, when I feed the 1k signal back to the FG it reads 1k. If I feed an external 1k signal (calibrated by my DSOs hardware counter) the FG reports that it's off by 5%. So, this issue affects the signal generation *and* the counter by the looks of it.
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Can anyone check if they have the same amount of distortion at frequencies higher than 18,2MHz?
I am beginning to suspect that I got a faulty unit.
Signal-Settings: Sine-Wave, 1V Amplitude, 0% DC-Offset.
Measured with an Advantest R3131A Spectrum Analyzer.
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I should also have mentioned that the FGs own counter is also off by 5%. So, when I feed the 1k signal back to the FG it reads 1k. If I feed an external 1k signal (calibrated by my DSOs hardware counter) the FG reports that it's off by 5%. So, this issue affects the signal generation *and* the counter by the looks of it.
They're both based on the same internal clock, so they'll both be affected.
I haven't heard of one of these being that far off, not that I've seen a large number of these generators. However, if you have access to a GPSDO, Rubidium, or other high-stability oscillator or a counter with one as its external clock, that'd be a better basis for verifying your signal generator's accuracy.
If you're using an oscillator directly, use your scope to compare its output signal to that of the 3224 at the same frequency. You'll see how much drift there is between them. Alternatively, if your scope can accept the oscillator's signal as an external clock, then that'll improve the scope's accuracy for measuring the generator.
With a universal/frequency counter that has a highly stable external oscillator, you can directly measure the generator's output frequency.
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Well, whatever about the level of inaccuracy, I'm considering it defective. So, I'm now considering my options and it's not looking good. I could try returning it to the chinese ebay retailer, but I could end up with more losses. If I had to keep it, I might try a repair. Anyone have any ideas about where to start looking? I assume it's clocked by a crystal, so I could start there? I'm guessing it also has some kind of frequency multiplier, maybe a PLL? Of course, that's likely to be embedded in the fpga - hmmm. Not good.
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Compare the signal to WWV or similar using an oscilloscope?
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The frequency should not be off by more than about 0.05% - so if 5 % off there is something wrong. Usually also a DSO and and most DMMs should not be off so much. A non locking PLL could be a reason - as this is likely inside the FPGA there is little on can do to fix this. If you are lucky it could be something like a wrong crystal of maybe an missing / not connected (e.g. bad solder) decoupling cap that brings the PLL out of function.
For the distortion at high frequencies close to there upper limit, I am not surprised to see a lot of spurious frequencies. This is about normal for an DDS without a good reconstruction filter and poor DAC. I have even expected more harmonics.
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Hi everyone,
eventually I have discovered a bug in the Manual Trigger mode of the FY3224S. In order to not overload this topic, I opened a new one on
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-function-signal-generator-manual-trigger-has-bugs/ (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-function-signal-generator-manual-trigger-has-bugs/)
Greetings,
mcmusic
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How complex of a waveform can be downloaded to the memory of the FY3224S, given it 2048 byte limitation? Would it be possible to simulate a signal such as the example shown below:
(http://img.photobucket.com/albums/v734/genejockey/Watch%20Timing/Tick.jpg)
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Also, one of the previous posts mentioned a USB isolator (http://www.ebay.com/itm/NEW-USB-Isolator-Magnetic-Coupling-Isolation-ADUM4160-USB-to-USB-/141998972441?hash=item210fcc5e19:g:aVAAAOSwEa5XPrRb (http://www.ebay.com/itm/NEW-USB-Isolator-Magnetic-Coupling-Isolation-ADUM4160-USB-to-USB-/141998972441?hash=item210fcc5e19:g:aVAAAOSwEa5XPrRb)) as well. Anyone tried this? Would be simple way to fully isolate the device, albeit between the USB isolator and PSU isolator would almost double the unit's price.
Also found this one with a ADUM3160, It's quite small and cheaper but not full speed.
http://www.ebay.com/itm/1500V-USB-to-USB-Isolator-Board-Protection-Isolation-ADUM4160-ADUM3160-Module-/201771509748?hash=item2efa84e7f4:g:N8YAAOSwUKxYa8xz (http://www.ebay.com/itm/1500V-USB-to-USB-Isolator-Board-Protection-Isolation-ADUM4160-ADUM3160-Module-/201771509748?hash=item2efa84e7f4:g:N8YAAOSwUKxYa8xz)
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Guys, using a 220v/220v isolation transformer would fix the grounding issue? It would have the added bonus of being a floating generator.
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The isolation "problem" is due to the capacitor needed to ensure EMC. Like with many other switched mode supplies that don't use PE, they have two small class Y caps (e.g. 5 nF range) from both of the mains lines to the output ground. These are more or less needed to prevent RF interference from the switcher. Just an isolation transformer would solve the problem, but is rather heavy. In this case the fully linear supply would be the more logical choice - if could be an old heavy wall wart and linear regulator in the case.
The original generator should be already floating, except the USB and the RF caps. The transformer will not isolate the USB of cause.
I think for the USB, there is an easier solution than doing it at USB level - AFAIK there is video showing the USB isolation inside together with a linear supply mod. AFAIR the USB goes through a UART to USB bridge anyway and isolation could thus be done at UART speed.
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Hi guys, just received my new FY3200 24MHz FG today and I've noticed that the frequency is off by approximately 5%. So, when the FG is set to 1k the hardware counter on my DSO reads 952Hz and at 10k it reads 9.52k. My DMM has a basic counter and it gives the same reading as the DSO. There's no offset; function=sine. Have I done something wrong? Is this a common problem?
it seems that my unit has the same problem. I think that this is a weird software problem.
I got the thing from banggood and after struggling around with them 5 weeks to get appropriate support they told me an undocumented calibration function that resets the unit. Press the left-arrow and the param key together, switch the unit on, wait 2 secs. Then you come into a calibration menu. Don't change this value (write it down), press the blue turn knob. You can also monitor the Ch1 Signal to set a exact value. If you power cycle the unit, the produced frequency is right.
BUT my unit disadjust and produces the wrong frequency when I use the sweep-Function in a particular way ! In detail, I set the start frequency to 0Hz and store it with the blue knob, then I set the stop frequency to some value (1kHz for example), store it, set the time (3secs), store, let the sweep run for some cycles, press the Ch1-Button to switch to normal mode, switch the unit off, switch it on again: frequency is off 15% or like.
My unit has software version 3.5.
Can you confirm that your unit has exactly the same problem ?
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it seems that my unit has the same problem. I think that this is a weird software problem.
I got the thing from banggood and after struggling around with them 5 weeks to get appropriate support they told me an undocumented calibration function that resets the unit. Press the left-arrow and the param key together, switch the unit on, wait 2 secs. Then you come into a calibration menu. Don't change this value (write it down), press the blue turn knob. You can also monitor the Ch1 Signal to set a exact value. If you power cycle the unit, the produced frequency is right.
BUT my unit disadjust and produces the wrong frequency when I use the sweep-Function in a particular way ! In detail, I set the start frequency to 0Hz and store it with the blue knob, then I set the stop frequency to some value (1kHz for example), store it, set the time (3secs), store, let the sweep run for some cycles, press the Ch1-Button to switch to normal mode, switch the unit off, switch it on again: frequency is off 15% or like.
My unit has software version 3.5.
Can you confirm that your unit has exactly the same problem ?
Thanks for posting that. My offset was more like 25% (125Hz reading was actually more like 100Hz) - but now aligns with the DSO and DMM. Many thanks!
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Thanks for posting that. My offset was more like 25% (125Hz reading was actually more like 100Hz) - but now aligns with the DSO and DMM. Many thanks!
Does it deadjust again if you use the sweep function (like I described) ?
Mine does and this makes the reliability of the unit more than questionable.
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Thanks for posting that. My offset was more like 25% (125Hz reading was actually more like 100Hz) - but now aligns with the DSO and DMM. Many thanks!
Does it deadjust again if you use the sweep function (like I described) ?
Mine does and this makes the reliability of the unit more than questionable.
Hey RIchie...well I followed your test...and yes, does the same thing. Even easier...it looks like it's tied to when you save the end freq parameter.
Looks like some overflow error somewhere...but can do this.
1. Set frequency to 60Hz, 3.00v, Sine
2. Press 'sys' button once (to select "save p_on freq")
3. Press blue button to save it
4. Press 'parm' to go back to main menu
5. DMM reads 60Hz
6. Power cycle reads 60Hz
7. Press 'sweep' three times to select "Sweep end freq".
8. Set to "1000.00Hz"
9. Press blue button to save
10.Power cycle
11.DMM now reads 52Hz
12.Power cycle and press "Parm" and left arrow together for two seconds while starting up.
13.Press blue button to save
14.Press "Parm" button
15.DMM now reads 60Hz
Seems to hold this setting as long as you don't save your end sweep frequency. :) I think it's reliable enough....but a little on the buggy side. For your info, if you change the end frequency value, you change the error offset in the process!
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Hi all, yesterday i have replaced the original psu from my f3224s with one of the "Hiland DIY USB Boost Single Turn Dual Power Module Linear Regulators Multiple Output Power Kit" ( Input voltage: 5-24V DC, Output voltage: + 12V, -12V, + 5V, -5V , +3.3V, Output current: 300mA (per channel) ) like the one in this video
https://www.youtube.com/watch?v=FvDSliwRE_w (https://www.youtube.com/watch?v=FvDSliwRE_w)
The unit can power on and the buzzer do the beep, but no interface on the screen and no response from any input.
After this i have reinstalled the original psu and measured the +-12V output pins with a result of about +-16V...
Any hint about this?
UPDATE: powered with 20V 1A and it's working, need to check with oscilloscope the waveforms (and study the theory behind ;D )
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Today I received my FY3224S unit from bang good:
It's hw version 3.6 and the software on the cd is v3.0.
A sine wave of 1kHz shows on my Rigol DS1054Z as 1.0001kHz. Pretty spot on.
Edit: it's hw version 3.6
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My version of using transformer isolation to reduce residual voltage and leakage current.
initialy i had 46vac to ground and 30 ua leakage current. now 0
The isolation transformer i used is a 50va (yes it's overkill) triad N-68X
you can source it from most of the usual places, mouser, newark, digikey and so on for about 17 usd.
I got one off ebay pretty cheap as a pull. It is "electrostaticly shielded" and i attached the shield to the ground of an EIC inlet filter.
i drilled 2 holes and bolted down the transformer using 10-32 nylon pan head screws and nylon bolt so no exposure of the transformer outside the case.
nibbling out the power opening I bolted in a filtered EIC plug i had in my parts drawer. delta electronics 06GEEG3E It can be had for 6 bucks at most places.
just for good measure i also added a rf choke to the dc lines. It is probably not needed but i had it on hand and threw it on.
here is some pics on how it turned out..the layoyut worked out very well, and very neat and it was a pretty quick install.
i was a bit worried about noise from the power supply having moved it near the pc board, but so far the output looks clean post install, well as clean as when i started anyway.
note: the center 'black' wire you see on the picture on the secondary is NOT a centertap, that is the electrostatic shield connector, it is usual it is white but i had to bodge on a wire as it was chopped short when i received it.
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That turned out nicely, inkeeper. :-+
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I have just tried the 1 khz 2khz check on my FY3224S using my DS1054Z scope on CH1 and Ch2. Observing the display in XY there is a slow drift in the lissajou display. A complete cycle of the the difference takes just under 3 minutes (about 2 secs under). Also the scope frequency meter (on CH1) seems to cycle between 999.999 hz to a minimum of 999.997 hz. Just to be sure I checked with both sources set to 1khz but one channel set to a 45 degree phase difference to make it easier to watch. There was no noticeable drift under this circumstance although the frequency counter on the scope CH1 still showed a drift as mentioned earlier.
Interesting.
John
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Hi guys,
for the workbench use of the FeelTech FY3224S I made a card for quickly looking up the available preset waveforms without looking into the manual. The "x" and "-" reflect that one can change the frequency of all PREx and ARBx waveforms, but not the duty cycle.
I have also made space for the arbitrary waveforms and the 20 memory spaces - just fill out by hand what you have stored under which ARB or Memory position, for example
Select. NAME f duty Voltage and offset
ADDR4 Square 1.024 kHz 30% 5V+2.5
I found it interesting to see that the 2 TTL connectors in the back put out not only the same frequency as the corresponding channel in the front, but they do have a variable duty cycle - an adjustment which seemingly did make no sense in case of a selected sine wave on CH1 or CH2, but the duty cycle entered here (as well as in all other waveforms) appears on TTL A (or B for CH2). So these TTL connectors are just great if you need a signal for any digital input. You do not have to pay attention to the amplitude and offset value if you adjust for a square wave on CH1/2, the TTL outputs deliver the adjusted frequency and duty cycle always with 0-3.3V, enough for both 3.3V and 5V designs.
I made the x-dimension of the card just wide enough that it can fit between the 2 front legs of the case (print it about 10cm wide). With adhesive film and 2 cardboard stripes I made a simplistic mount: I can slide the folded card (printed on stiff paper) into this mount for fast storage and retrieval.
Maybe that is of help for some of you.
Greetings from Germany,
mcmusic
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Very cool mod! German engineering and inventivity! :)
FeelTech ... Das Signal Generator :)
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Great idea. Thank for sharing!
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Another successful modification. My unit is 25 Mhz with firmware 3.6V
a) C14 socket with ground
b) Fuse socket
c) Earth / floating ground switch
Thanks for this thread
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Nice work, Horacio. Looks like it was made that way. :-+
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HI! I just got my brand new FY3224S signal generator - Can anyone explain to me the value or the use of a DC wave...?
Thank you!
Derosoft
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You can change the Offset and get different DC Values.
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Hi all, i'm new in that forum and i need your help to solve a issue if is possible.
Recently i acquired a Fy3224s, but the signal generator have a issue.
Cannot adjust the signal generator in frequency, the screen show a frequency but the signal is more high.
Ever is 0.3x factor over that the screen show in hertzs.
For example, if i want to use 1000khz, then i need to put 700khz and then the signal is 1000khz in any signal.
If i use 2Mhz then i need to put 1.4Mhz.
And ever is the same, someone know how i can solve this problem?
See the images plz.
Thx for your help.
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Mike,
Try this:
1. Turn off the function generator.
2. Press and hold "Parm" and the left arrow together, then turn on and continue to hold for two seconds.
3. Press the blue knob/button to save
4. Press "Parm" button
Does the displayed frequency now match the output frequency?
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WOW really fast reply and worked perfectly!!!
Thx for your help.
Thx, thx, thx. :-+ :-+ :-+ :-+
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Glad to hear that fixed it. There's a firmware bug that several members were discussing on the prior page. It appears you triggered it on your generator, too.
Here's the original post where the calibration reset procedure was outlined:
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1135001/#msg1135001 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1135001/#msg1135001)
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Dear forum,
A question about the amplitude range of these cheap signal generators:
If you want to use this kind of signal generator for testing transistor amplifier circuits, it should also support amplitudes in the mV range.
(http://www.ktword.co.kr/img_data/4820_2.JPG)
Do these cheap DDS signal generators support these tiny amplitudes?
If their minimum amplitude is 1V, this sort of renders them useless for these kind of lab experiments.
Are both channel outputs identical in terms of precision and min/max amplitude range?
Regards,
Laseractive
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On my FY3224S, the settable resolution for amplitude is 10mV. It will output down that far, but a sine wave that small has a lot of distortion and the amplitude isn't super accurate. 1V will produce a much cleaner signal.
If you need a good, small sine wave with a cheap generator, select an amplitude that produces the best waveform and then put an attenuator on the output.
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Just wanted to show @laseractive what he can expect from these units. I'm not using a BNC Feed-Thru 50 ohm adapter. It's still in the mail.
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At 2mV/div you can probably see the distortion better (and get more accuracy on the measurements).
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Many thanks richie, bitseeker and claytonedgeuk for the tips on recalbration. Was pulling my hair out trying to figure why the generator said it was putting out a 10khz signal but my scope was saying 11.3Khz. This tip worked brilliantly, thank you so much!
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Glad that worked for you. It's interesting that there are more posts about this frequency problem lately.
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On my FY3224S, the settable resolution for amplitude is 10mV. It will output down that far, but a sine wave that small has a lot of distortion and the amplitude isn't super accurate. 1V will produce a much cleaner signal.
If you need a good, small sine wave with a cheap generator, select an amplitude that produces the best waveform and then put an attenuator on the output.
That is the problem with the FeelTech, at very low voltages (mV) you get too much noise, so the solution of the attenuator sounds perfect however I don't know exactly where and what attenuator should I buy!
BTW, does a Linear Power Supply solves the low voltage noise issue?
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Typical RF attenuators should work fine as long as they cover the frequency range that you require. For example, the HP 355C and 355D attenuators work from DC to 1GHz. There are fixed (one attenuation amount) and adjustable kinds.
If buying used, be sure that they still work. Often, they've had too much power put through them and their internal components have been fried.
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Can it make modulation? AM or PWM?
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Can it make modulation? AM or PWM?
See: https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg741894/#msg741894 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg741894/#msg741894)
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Here is my power cord mod to ground the unit. (Plugs into one of the TTL rear panel bncs)
($19.95 free shipping :)
Mine was missing the CD.
Is there a link to the software and manual?
T
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Hi all. I just purchased 5he FY3224S and I am wondering if its possible to set the frequency / period of the square wave to greater than 1 second for instance. Can I set it to a 5 second period for example?
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I've never tried it. See if you're able to. It won't break.
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yes, I used it over days and days. Turn frequency to 0.2Hz for 5 Seconds period or to 0.1Hz for 5 seconds on time.
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Hi! For anyone that is interesetd, i've made some measurements of the on and off resistance of the altera chip. For reduce the dac error first i've tried to increase r-2r values from 499/1000 to 1000/2000, but someone here pointed out that the accuracy eventually will be reduced by this mod.
So i've measured the resistances, and i've found that when warmed up has an Ron of near 9,53ohm, and Roff of 7.86 ohm. Average near 8.7 ohm (rounded 9 ohm)
I've also glued (with apposite themal conducting glue) a big dissipator over the altera chip for mantain the temperature as stable as possible.
So, remaining around the same 500/1000 orginal range we need or 491/1000ohm, 500/1018ohm or similar values.
Now i need to try to find some hign precision resistors with this values...
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If you really want to improve things then you better find a DAC which doesn't glitch when changing between codes and wire that in. The current solution they used depends on the assumption resistors next to eachother on the same reel have the same error. Getting better than 8 bit resolution from an R2R network is pushing the limits so don't bother going into that direction.
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With 1k/2k solution i've got an accettable error (the signal is linear and the glitch is almost inexistent), so if i try to retain the (almost) 499/1000 r-2r solution, but with resistors matched with the ron/roff of the altera chip, i think that i can get the best of the both worlds without having to wire in a better dac. For the amplitude i've already substituted the original hc4053 analog switches with the low ron version adg733 (with the supporting mods).
If i'll have to substitute the dac, i thing that is better to simply throw away the feeltech and buy a better signal generator. I want only to make it "acceptable"...
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I received no disk, but was able to find the software online.
However, the "FY3200 PC Contrl Software" shows a version "(c)???? ?????????????????"
Does anyone have a newer version?
Tom
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... I am wondering if its possible to set the frequency / period of the square wave to greater than 1 second for instance. Can I set it to a 5 second period for example?
Hi stuartmp,
the other day I was playing with an Arduino and wrote a few lines to measure some square waves of the FY3224S in the low frequency region. I was surprised to see that at 1 Hz and below the FY3224S begins to develop a noticeable deviation to the theoretical values.
At 1Hz, the measured period is 1.0053 secs, which is 0.53% too long. In the slowest position of 0.01Hz the period should be 100 secs, I measured 178.95 secs instead, which is 79% (!) too long.
So be aware if you want to use the very slow waves for quantitative measurements.
For anyones convenience I attach the results with other low frequencies.
Greetings from Germany
mcmusic
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Sorry to bring up the power supply issue but just wanted a quick verification of my plan to modify my FY3224.
At the end of the day I used:
- 2 pieces PRINTTRAFO (PCB Transformer) Gerth 2X30V 5,6VA #V050561 @ Voelkner.de (cheaper (5,47 EUR each) and I have shipping flat rate) or
I'm planning on using a single Hammond 160H120, [120V C.T., 200mA 24VA], transformer inside the enclosure to provide the same isolation as "classical" demonstrated. The local electronics supply can order in this part but they have stock on a Hammond 160G120, [120V C.T. 85mA 10.2VA]. Is this smaller transformer sufficiently sized as to not overheat in the enclosed space or should I actually purchase and install the larger transformer? My gut says it might be OK since the capacity is only slightly smaller than "classical's" transformers.
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I can report that I had the signal generator for several weeks in continuous operation (but with a high impedance load) without any thermal issue. I can check the real power consumption in W and VA under 50 Ohm load on both channels in a few hours.
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Under full load (both channels 20V@24MHz loaded by 50 Ohms) mine draws 8.5W // 14.2VA on the primary side. As far as I know the transformers are rated regarding the secondary side.
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Hi stuartmp,
the other day I was playing with an Arduino and wrote a few lines to measure some square waves of the FY3224S in the low frequency region. I was surprised to see that at 1 Hz and below the FY3224S begins to develop a noticeable deviation to the theoretical values.
At 1Hz, the measured period is 1.0053 secs, which is 0.53% too long. In the slowest position of 0.01Hz the period should be 100 secs, I measured 178.95 secs instead, which is 79% (!) too long.
So be aware if you want to use the very slow waves for quantitative measurements.
For anyones convenience I attach the results with other low frequencies.
Greetings from Germany
mcmusic
Curious what makes you so sure those results are due to the generator and not to your code, arduino, or test setup?
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Rounding errors? Accumulating interrupt calls? Maybe.
I would not trust an Arduino Micro in keeping times for more than a few seconds, for example. Perhaps mcmusic would want to share his/her setup and code with us.
At any rate, the 100 vs 170 seconds discrepancy can be verified in less then 3 minutes by hand...watch.
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Hi Sredni,
you are quite right, you can measure the pulse time for 0.01Hz or 0.02Hz easily with a stopwatch; I came out very close to the Arduino-measured times.
Of course I can share the code, but it is no masterpiece, more a quick hack. I just wrote it for this special purpose. It can not measure more than slow pulses because I used Serial.writes in the ISR. For faster applications one should not do this. Please don't blame me anyone who can write faster code - it just wasn't needed. Below say 20Hz I think this code measures quite well, if you run it on an Atmel 328 with a precise 16 MHz crystal.
I really would like to know if other people's generator are that much off in these very low frequencies.
The setup is quite obvious: connect the 2 GNDs (of generator and Arduino), and connect the generator's hot pin with pin 2 of Arduino. Adjust it to output a square wave between 0V and 4 V.
Greetings,
mcmusic
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I didn't try the AAM (Arduino Automated Measurement), but I fed the signal into my scope (*) to have a look.
While the DDS is not incredibly accurate at the extreme duty cycle and frequency given, I saw no sign of the dire discrepancy you are reporting. Maybe I did not look long enough, but when set to 0.01 Hz with 0.01 duty cycle I get pulses separated by about 100 seconds.
Verified in normal and roll mode several times.
The width of the single pulse appears to be less than 1000 ms, but it's close enough. There is a slight variation from pulse to pulse, but it's hardly noticeable.
As a side note: at 1 kHz the automatic measurements of the Rigol scope (they are based on the pixels shown on screen, not actual memory) are spot on. But this might have more to do with the fact that I had only two pulses on screen and not three, so there were more pixels to make a better assessment.
(*) The overshoot you see in the pulses is due to the fact that I fed the signal into the high impedance input of the scope. The generator behaves better with a 50 ohm termination, of course, but I do not believe this could have affected time measurements in a significant way.
P.S.
I thought I had many more screenshots, but it appears that when my Rigol hit sequential number 43, it decided it was not worth saving them anymore. Also when I tried to open the last screenshot taken on my PC it made it throw a blue screen of death. Not the first time. Really sudden death, everything but the mobo and cpu stopped, and that includes all fans. And the blue screen message says "windows has stopped to prevent damage to your computer". WTF! |O
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On my FS3200S I also get 178s periods when set to 0.01Hz.
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Did you guys try the reset manouver described a few pages back?
Maybe it can be fixed.
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I was just about to say that. It sure sounds like your calibration needs to be reset.
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1175563/#msg1175563 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1175563/#msg1175563)
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Hi all,
thanks for your test and pics, Sredni. Interesting that you measure the 100s period time for 0.01Hz exactly.
Also interesting is that nctnico measures exactly "my" value of 178 sec for 0.01Hz.
It seems that Sredni has a different machine compared to nctnico's and mine.
BTW, my SW Rev is 2.0, 2010-2014.
To help clarify, I made also measurements for 0.01 and 0.02 Hz with the scope, see attachments.
The Arduino and the scope measurements are quite similar, 178.949sec (Ardu) against 179.2sec on the scope.
If you look at the 4 subsequent Arduino measurements, you see that they are quite stable (aside from a very little thermal drift after switch-on in the last position). This speaks for stable conditions both of the FY3224S and the Arduino. Yes, I do trust these Ardu results, particularly because they can be checked with a stopwatch so well and easily.
Some wrote that I should make a calibration reset. I am pretty sure that this is not the cause, because between 10Hz and 23 MHZ I have a really great accuracy in the respective period times.
I made a reset anyway, but I dont't think it worked right. I followed this post
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1135001/#msg1135001 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1135001/#msg1135001)
and never got into a "calibration menu" and I did not get a value to write down. When I follow the reset procedure all I get is a - sign (minus sign, top left) after about half a second, no matter when I release the 2 buttons after 2 secs or more.
Greetings,
mcmusic
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I have software revision 2.0 2010-2014 as well.
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I'm on 3.5. Bought last December. (Last version seems to be 3.6)
So maybe that's one of the things that were fixed.
Sorry, guys, I'm not aware of any means to update the firmware of this thing.
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Good day all,
has anyone managed to positively ID the op amps in these sig gens, because I need to replace one which is buggered.
Somewhere back in this thread, there is a link to a TI datasheet for a "THS3002", but during my searching I also came across this:
https://e2e.ti.com/support/amplifiers/high_speed_amplifiers/f/10/p/502262/1819948
You would think that TI would know their own devices and it is not uncommon for manufacturers in certain countries to re-mark IC's in an attempt to obfuscate any ID attempt.
Any hint of another suitable, drop-in replacement would also be greatly appreciated.
BTW, I have confirmed the op-amp itself is knackered, as I swapped the one from CH1 which wasn't working, with CH2 which was, and the previously-working CH2 is now dead. I have all the functions on CH1 again now, so I'm not too bothered about leaving it as-is for a while and getting back to it at a later date.
Regards.
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anyone seen one of these yet:
https://www.banggood.com/RD-JDS6600-DDS-Signal-Source-Dual-Channel-Arbitrary-Wave-Function-Generator-Frequency-Count-p-1148682.html?rmmds=search (https://www.banggood.com/RD-JDS6600-DDS-Signal-Source-Dual-Channel-Arbitrary-Wave-Function-Generator-Frequency-Count-p-1148682.html?rmmds=search)
3 models up to 40mhz
Looks like a viable alternative to the FY3224S, also looks to be powered by a wall wart,,,
Google search brought up only a couple of pages of hits, all ads...nothing on Youtube yet either...
cheers
Gary
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Here a more detailed view
https://world.taobao.com/item/549827466535.htm?spm=a312a.7700714.0.0.CyQUZQ#detail
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Hi All,
I am just wondering if its possible to generate a Square wave using the FY3224S that is slower that 0.01hz ie. 100 Seconds
I am trying to check the charge time of a large capacitor on my oscilloscope and I would like a longer time period.
Any advise on this would be very much appreciated.
Cheers.
Stuart
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you could build clock dividers with ttl logic chips ?? divide by 10 by 100 by 1000 it depends how many dividers you want, there's divide by N chips
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Hi every one! I've been reading it seems all of the post here and I still have a question? What is a DC Wave??? How would you use that?
Thanks,
Curious
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Hi every one! I've been reading it seems all of the post here and I still have a question? What is a DC Wave??? How would you use that?
In general:
That is intended to output a DC value. I'm hesitating to write that it is somewhat accurate but depending on the function generator it may be more accurate than a generic power supply. Also the output of a frequency generator has a 50 Ohm resistor in series so it is less likely you break something.
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Hello,
I got my FY3224S 24MHz from Banggood (with discount and priority direct mail under 55 Eur).
Firmware 4.0 2010-2017
Calibration is good: +40Hz at 10MHz (measured with calibrated PM6624)
Calibration stays after you use sweep (and power cycle).
Manual trigger mode ok, no issues. Ref.: https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-function-signal-generator-manual-trigger-has-bugs/ (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-function-signal-generator-manual-trigger-has-bugs/)
All waveforms can be set up to 24MHz (with the usual distortion on waveforms other than sine above 6MHz)
If you change any parameter there is still an interruption of signal generation of 1.36ms.
I will to the power supply mod with https://www.banggood.com/DIY-USB-Boost-Single-Turn-Dual-Power-Module-Linear-Regulators-Multiple-Output-Power-Kit-p-1022517.html (https://www.banggood.com/DIY-USB-Boost-Single-Turn-Dual-Power-Module-Linear-Regulators-Multiple-Output-Power-Kit-p-1022517.html) and power it from a heavy wall wart with transformer.
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Hello
Does anybody know if firmware can be updated or if it can be cloned with an IC programmer?
Thanks!!
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I haven't yet seen anyone upgrade the firmware in theirs. Even the manual on FeelTech's download page (http://en.feeltech.net/html/download/) is for firmware version 1.4.
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Hi,
i received my FY3200S yesterday. I changed the USB serial converter to a FTDI, but cannot get it to communicate from PuTTy terminal. Connections are as with the CH340 module, RX of mainboard to TX of the USB adapter and vice versa, Gnd to Gnd and VCC floating (it seems floating on the CH340 board because it is powered from the usb port. 5V are provided from the mainboard but not used by the USB bridge.) The FTDI module is set to 5V. I had checked before on the oscilloscope that the original board outputs TTL level.
The motivation for the modification is that on my office computer the CH340 driver won't install.
What are the communication settings, i read somewhere 9600, 8N1, and tried both this and 57.6 kbps.
I also put the FTDI board in loopback configuration (RX and TX tied together) to exclude that this is the problem, but it works, i see the echo of my typing on the terminal.
Is there any sequence to initialize external control or a combination of buttons to press on the function generator to enable remote mode?
I regret i had not tried at home to communicate over the original module from PuTTy.
The bluetooth to serial module mentioned earlier in this thread is also a nice feature!
Thanks for any hints
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Good day all,
has anyone managed to positively ID the op amps in these sig gens, because I need to replace one which is buggered.
Devttys0 goes over the default amplifier op amps used and even suggests a better slew rate replacement, as well as some other improvements, worth a watch.
https://m.youtube.com/watch?v=-xOKNi8M3xE
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The better amplifier is definitely an improvement.
Changing the filter is a 2 side thing: it makes the square wave sharper, but it will also add image frequencies to the sine output.
The square wave still have a big problem with jitter at other than a few special frequencies. So get a really nice square one would need to add a sine to square wave converter circuit (e.g. comparator and maybe optional divider). In this case the original filter would be better.
There is also the rather poor DNL of the ADC when the highes bit changes. It might be worth to adjust at least the highest bit.
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I just modded my FY3224S with a proper 3-wire grounded power cord... and managed to blow up the power supply board, (in spectacular fashion I might add), in the process of making this thing "safer". :palm: I won't go too deep into my faux-pas, but suffice it to say that you are supposed to connect the SECONDARY-side-gound (low voltage DC ground) to mains-earth-ground. Do NOT, under any circumstances, connect the PRIMARY-side "ground" (from the bridge rectifier) to mains-earth-ground. That isn't a meant to be earth-ground. It's the ground "reference" of the primary.
I've noticed that FeelTech is using whatever power supply they can get their hands on, as mine looked nothing like the ones posted by med6753 & tombddiver. My unit came with a very nice SICO-650 power supply. (Well, it WAS nice 'till I fried it). I put in a "Universal DVD Replacement Power Supply" I managed to find on Amazon. It took some searching to find one with the required +5v & +/-12v outputs.
My mod included a toggle switch in the grounding path, in case I ever have the need to "float" the BNC outputs, the way the unit is shipped from FeelTech. Otherwise that switch stays in the safe/gounded position.
One more note; The sticker on the bottom of the unit is printed on an ink-jet printer. If it gets wet, it will bleed and smear.
My Feeltech also has the SICO-650 switching power supply. If it's as good as you say what is the point to mod this Signal Generator nowadays? :-//
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Hi,
Does anyone have the version with a PSU that has 2x 5V and +18V -18V outputs? The measured values for 5V are around 5.5V, whilst the +18V is around 17.8V, and -18V is around -16.3V (from memory).
I measured the voltage at the BNC outputs and it seems that there is about 3.3V AC. I was going to modify the PSU as per https://sdgelectronics.co.uk/feeltech-fy3200s/ but now I am wondering if its worth it especially with now more commonly available transformers becoming 24V and no centre taped ones. The model on the board is SCL021 V1.5 .
Also, the USB input board has an IC with some resistors one it, and a capacitor. Also an improvement?
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My version of using transformer isolation to reduce residual voltage and leakage current.
initialy i had 46vac to ground and 30 ua leakage current. now 0
The isolation transformer i used is a 50va (yes it's overkill) triad N-68X
you can source it from most of the usual places, mouser, newark, digikey and so on for about 17 usd.
note: the center 'black' wire you see on the picture on the secondary is NOT a centertap, that is the electrostatic shield connector, it is usual it is white but i had to bodge on a wire as it was chopped short when i received it.
Hi innkeeper ,
You have board version 1.5. What is your voltage rail outputs? +5,+5,+18 or +12?,-18 or -12?
Mine are +18,-18 but I am wondering if they sig gen will run of +12 -12 anyway.
How successful is your mod? I am considering replacing the whole supply board but curious if your style is still as good at reducing the output AC.
Cheers
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Since i used a real isolation transformer, it was 100% successful.
0 leakage current
I'm still very satisfied on how it turned out.
I don't know what my rail voltages are, id have to measure.
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Would you be able to check the labels on the rails?
No leakage current, and not leakage AC voltage? I measured no leakage DC on mine but there was AC. To be honest I wasn't sure where the current was being measured. Between the centre of BNC to outside of BNC?
I am trying to understand if the issue is the power board not isolating or if it's the board outputting when it shouldn't be.
Last, your EIC inlet filter, do you know if it improves anything? My question is if some of the noise on AC power is coming through the whole system and if in your situation the filter provided cleaner power and then isolation provided the safety. As that really would be a simpler approach then building a whole new supply.
Thanks.
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The rather high AC voltage / leakage current is not specific to the Feeltech unit. It is a general properties of switched mode supplies with only a 2 pin plug. To meet EMI regulation limits this essentially requires a small capacitor from the output to the input side. Without a dedicated ground or neutral (so UK and Ausstralian plug might have an advantage here - but not the more common US or EU one, so units are often not takin advantage of knowing which pin is neutral), there is no good point on the input side. The best they can do an usually do is having 2 cap to both pins. So normally one will see half the mains voltage and a small but measurable leakage current to ground.
The easy fix would be to have a 3 Pin plug and cable and use a suitable filter toward PE. Connecting the GND to PE would be an other option - though it could cause trouble with ground loops, as most scopes are grounded too.
The leakage current to ground is usually measured form the outside of the BNC to GND (PE). However it does not make a significant difference measuring from the BNC center pin. Usually the current through the class Y caps should be relatively small and well build other instrument should be tolerate the possible discharge current on connection. So the voltage measured is not such aa big deal.
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The rather high AC voltage / leakage current is not specific to the Feeltech unit. It is a general properties of switched mode supplies with only a 2 pin plug. To meet EMI regulation limits this essentially requires a small capacitor from the output to the input side. Without a dedicated ground or neutral (so UK and Ausstralian plug might have an advantage here - but not the more common US or EU one, so units are often not takin advantage of knowing which pin is neutral), there is no good point on the input side. The best they can do an usually do is having 2 cap to both pins. So normally one will see half the mains voltage and a small but measurable leakage current to ground.
The easy fix would be to have a 3 Pin plug and cable and use a suitable filter toward PE. Connecting the GND to PE would be an other option - though it could cause trouble with ground loops, as most scopes are grounded too.
The leakage current to ground is usually measured form the outside of the BNC to GND (PE). However it does not make a significant difference measuring from the BNC center pin. Usually the current through the class Y caps should be relatively small and well build other instrument should be tolerate the possible discharge current on connection. So the voltage measured is not such aa big deal.
Kleinstein, I'd like to check that I understand all the parts. I know a little about mains power but not a lot.
"To meet EMI regulation limits this essentially requires a small capacitor from the output to the input side". Output and input of the psu?
"The best they can do an usually do is having 2 cap to both pins". Does this mean literally wire from the mains plug -> cap -> psu? 1 cap on neutral and 1 on live?
"So normally one will see half the mains voltage and a small but measurable leakage current to ground." Could you explain why half?
"The easy fix would be to have a 3 Pin plug and cable and use a suitable filter toward PE." What is PE?
So is the linear power supply different because the transformer crates the decoupling and thus no capacitor is needed?
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There are litteraly 2 small caps: one from neutral to the output and one from the life to the the output. These 2 caps form a capacitive divider and thus one see's half the voltage. For safety reasons these caps are Y-rates types that a guarantied not to fail short. Usual capacitance is about 4.7 nF.
In principle a transformer power supply will show a similar voltage. Here it is from capacitive coupling in the transformer. However the capacitance is usually much smaller (e.g. maybe 1%) than the Y-caps. A linear supply does not need the extra caps because there are essential not RF emissions. Even a SMPS behind the conventional transformer can usually get away without.
PE is the short for protective earth, so the safty ground from the 3 rd. pin. If available one could have the capacitors from L to PE and N to PE and than either a direct connection from PE to the BNC or just a capacitor.
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Hey guys,
Does anyone have a schematic for this device? I recently damaged what I suspect will be the output amplifier for Chanel one. I accidentally connected the output to 30vdc forgetting the de-coupling capacitor..... |O
Everything still works ie it produces the signals they just have very little amplitude ie 200mV rather than 20v etc.
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I received mine today. The output signal looks pretty clean and reasonable, however the unit itself crashed too often (especially when I turn on both channels and try to witch between channels and change the settings frequently). Is this normal (if yes, WTF!!) or is it possible to update the firmware and make it more stable?
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Question before I push the buy button, I was about to buy a XR2206 7 bucks signal generator and then it was out of stock.
Now I don't want to do anything high tech fancy stuff right now but if I spend 10* the money and get this one https://www.banggood.com/DANIU-FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1157268.html?p=ZW051057416242016088 (https://www.banggood.com/DANIU-FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1157268.html?p=ZW051057416242016088) will it be worth the money?
For now what I want to do is making a led blink and if possible trigger the scope through the back output of this.
I need a blinking led to test camera latency.
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For blinking an LED, you could just make an oscillator circuit very inexpensively to drive it (LC, crystal, 555 timer, etc.). So, spending $70 for that purpose is overkill. However, if you believe that you'll have use for a variety of waveforms at a selectable frequency, and sometimes even two at the same time with different phase or frequency, then the FY3224S is an inexpensive option that works fine in general.
Keep in mind that this is not a high-end instrument and has its downsides, though some can be worked around: no user-accessible firmware updating, poor low-amplitude output (use an external attenuator), distortion near zero-crossing, high jitter between channels depending on frequencies chosen, high-voltage AC leakage (as covered extensively in this thread), etc.
For general hobby electronics use, these downsides aren't showstoppers, but as always, caveat emptor with any tool you buy. Know what it does and doesn't do well, use it accordingly, and you'll be just fine.
As for the price, unless you're in a hurry, you may want to shop around. I've seen the 24 MHz version occasionally for around $50.
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Question before I push the buy button, I was about to buy a XR2206 7 bucks signal generator and then it was out of stock.
Now I don't want to do anything high tech fancy stuff right now but if I spend 10* the money and get this one https://www.banggood.com/DANIU-FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1157268.html?p=ZW051057416242016088 (https://www.banggood.com/DANIU-FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1157268.html?p=ZW051057416242016088) will it be worth the money?
For now what I want to do is making a led blink and if possible trigger the scope through the back output of this.
I need a blinking led to test camera latency.
Depending on the speed you wanted you could do this by programming a small Arduino. For less than $5 you have extreme versatility and a built in LED along with USB programmibility.
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Hello
I bought two weeks ago FeelTech FY3220S. Firmware v.4.
It has another FPGA of 144 pins.
I have drawn a partial schematic of the Feeltech FY3224S,
using drawings from eevblog (masterx81) and from these links:
http://kiedontaa.blogspot.dk/2017/09/feeltech-fy3224s-reverse-engineering.html (http://kiedontaa.blogspot.dk/2017/09/feeltech-fy3224s-reverse-engineering.html)
It is a very good article.
See next post for Schematic.
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Hello
I have drawn a new partial schematic of the Feeltech FY3224S,
because in the first schematic I had made mistakes in the attenuator (HC4053).
So I hope you see this here.
New schematic is attached.
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Thanks for documenting this, g2, and following up with corrections. :-+
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Hello, thank you to bitseeker for nice words.
New schematic is attached.
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Can anyone supply from their own test equipment if capable, the harmonic distortion from their device at 1khz 1V unladen so that I can get a consensus as to the values people are getting.
I know what the documentation states. Im interested in real world values.
If your test gear input has a specific impedance, please specify
thanx
j
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He is a measurement using a Rigol DSA815
I can't do 1KHz so here is sinewave 1MHz -7.8dBm into 50 ohms.
The unit is the FY3224S 24MHz version firmware is 3.5.
Let me know if you want any other measurements.
Mark
G0MGX
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and here is a 1MHz signal at as close to 0dBm as I can get.
Mark
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Here are some traces using my Scotties Spectrum Analyser. The first trace shows 'No signal' to the MSA which illustrates the various 'spurs' that exist in the design albeit <-75dBm.
The second is from a home built Wien AF generator, uses an RA53 for old timers, set for 1K at ~0.2v o/p. The lower level is to avoid driving the MSA input mixer too much and creating IM distortion. The third trace is the Feeltech set at 1K and 0.2v o/p. Comparing the traces should help you see any differences and get a visual picture of the quality of the Feeltech's output. The 'Hump' at the beginning of the traces is the Zero frequency hump typical of Spectrum analysers and is the breakthrough of the first oscillator in the front end mixer.
Hope this helps.
John
Edit: NB. The latter traces show the rise in the Noise floor due mixing first oscillator phase noise.
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Could you do 10k or possibly 20K, I need a value I can match and 1mhz is too high. Sorry
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You should be able to find it for much less than $70 now..
Question before I push the buy button, I was about to buy a XR2206 7 bucks signal generator and then it was out of stock.
Now I don't want to do anything high tech fancy stuff right now but if I spend 10* the money and get this one https://www.banggood.com/DANIU-FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1157268.html?p=ZW051057416242016088 (https://www.banggood.com/DANIU-FY3224S-24MHz-Dual-channel-Arbitrary-Waveform-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-p-1157268.html?p=ZW051057416242016088) will it be worth the money?
For now what I want to do is making a led blink and if possible trigger the scope through the back output of this.
I need a blinking led to test camera latency.
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I bought one of these and have since built an isolating power supply and USB board. The isolator ICs arrived yesterday so I'm hoping to get the first board made later today but the power supply is right and the USB isolator is a standard circuit so should work.
NOTE: The 3D rendering has the positive electrolytic drawn reversed AND the 3 smaller electrolytic should be 100nF ceramics :)
So once I've got it built and working I should have some spare boards as it was only a few £ more for 10 than 2 and they sent me 11 anyway.
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Thanks for sharing, cowasaki. Is J6 for a switch to enable/disable earth ground?
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Thanks for sharing, cowasaki. Is J6 for a switch to enable/disable earth ground?
Yes it is. I thought there might be a use for it so added it just in case
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Yep, it's good to have so that you can float the generator.
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The last parts arrived today. The PSU is working so just needed a couple of resistors that I didn't have and now I can test the USB isolator. I didn't get to check this before doing the board but if it doesn't work USB isolators are under £10 anyway....
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Sweep function broken for some versions?:
Does anyone have an issue with the sweep function, too?
I have the FS2200S, and it also mentions sweep somewhere in the menu, but when I go through the steps I saw someone activate sweep in a YT video and compare, I see my menu hierarchy doesn't go that far, it gets stuck before*. I can't get it to work. Feeltech only replied once, giving the instructions I already knew and don't work.
* more precisely: when I press the PARM button on the "sweep" screen, all it does is switch between setting the time, and the lin/log.
I can't seem to get to set a start frequency which is always 0 Hz. I manage to get it from stop to run, but the freq does not move. Sweep time is set to 1 second. So if it's on run, it should do *something*? No output. Could I still be doing something wrong?
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Is it possible to max both channels at sine waves, 24MHz simultaneously? My unit crashes every single time when I try to set both channels even at 10MHz!
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On a quick check of mine it outputs a 24 Mhz sine on both channels without crashing. However there is an obvious low amplitude jiggle on the signal level, tested at both 1 volt and 10 volt levels, when set to 24 Mhz. Dropping the output frequency below 24 Mhz seems to reduce that particular problem although the signals do still have a few millivolts of amplitude modulation superimposed on the signals from both outputs. For the price one cannot really complain. It might be worth checking whether the internal PSU voltage rails remain stable for both outputs at their maximum frequencies and at various voltage output levels.
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The last parts arrived today. The PSU is working so just needed a couple of resistors that I didn't have and now I can test the USB isolator. I didn't get to check this before doing the board but if it doesn't work USB isolators are under £10 anyway....
Do you have any spare board blanks you want to sell?
Thanks!
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I'm not sure if I should press the buy button on this arb/sig gen linked below or the FY3224S that's been talked about a lot in this thread.
Unfortunately I can't find a model number
https://www.amazon.co.uk/dp/B0779V4B9R (https://www.amazon.co.uk/dp/B0779V4B9R)
The extra bandwidth (60Mhz) and *k samples @ 14bits interests me a lot.
Any obvious pitfalls that can be found with this one?
Thanks.
EDIT: It's the Feeltech FY6600S. They now have a FY6800S but I can't see any technical differences, just cosmetic differences and a bump in price.
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As long as the firmware on the FY6600 is fairly recent, it's probably OK, unless some of the hardware issues are important to you. Older firmware could randomly render the front panel inoperative. See the following thread for more than you ever wanted to know about the 6600 and a custom front panel firmware that's being developed (hence the high traffic in the thread):
https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/ (https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/)
The 6800 is supposed to address some of the hardware issues (high ghost voltage on output, no user firmware updating, etc.).
Edit: Looks like someone got a hold of a 6800: https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg1546058/#msg1546058 (https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg1546058/#msg1546058)
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Hi. I got a FY3200S and found the interface to be horrible (both hardware and software for Windows). The software is absolutely atrocious and actually sends frequency values 100 times smaller than it should.
In response to this I've started making a very simple program with the very basics. I plan to add sweep and counter options later. It is already working much better than the original software. Not sure if I will add the waveform upload thingy.
My question is: does anyone know if there is a serial command for enabling and disabling the channel outputs? Also I can only query values from the main channel. Haven't found a way to get values from the second channel. I was planning to make the program sync with the hardware so that it showed the actual settings as soon as the program started but this is making it impossible to implement for both channels.
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Hi. I got a FY3200S and found the interface to be horrible (both hardware and software for Windows). The software is absolutely atrocious and actually sends frequency values 100 times smaller than it should.
Yeah; I find almost universally that hardware manufacturers make terrible software - both embedded and PC.
The frequency values one I can easily understand - the serial protocol works in centiHertz, so maybe the PC software just forgets to account for that.
In response to this I've started making a very simple program with the very basics. I plan to add sweep and counter options later. It is already working much better than the original software. Not sure if I will add the waveform upload thingy.
My question is: does anyone know if there is a serial command for enabling and disabling the channel outputs? Also I can only query values from the main channel. Haven't found a way to get values from the second channel. I was planning to make the program sync with the hardware so that it showed the actual settings as soon as the program started but this is making it impossible to implement for both channels.
I too have been working on some control software, though mine is a support library for some more universal control program. I don't want to control just this siggen - I have plans to go much further more generically.
For now, what might be of interest to you is the serial protocol support in my module, which lives at
https://metacpan.org/pod/Electronics::SigGen::FY3200 (for source code view see the "Source" link in the left panel)
That doesn't (yet) have control of the frequency counter or sweep modes, but it does have as much of the main signal generator control as I could work out. In particular it doesn't do phase of channel 1, and it doesn't have output on/off control at all.
Next time I have the thing out, I may try brute-force guessing all possibly bytes of c{BYTE} and c{BYTE}0 to see if there's anything that might turn off a channel, but that technique aside I can't think of any other way we'd find it.
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I finally had time to modify my Feeltech FY3200S power supply by adding a 1:1 mains transformer 230VAC/230VAC Triad VPS230-110. Before modification the leakage voltage/current was 92VAC/90uA, and after modification the leakage voltage/current is around 15VAC/20uA measured** between the BNC gnd and the mains earth.
** Using UT-61E in AC-V / AC-mA.
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Hi. I got a FY3200S and found the interface to be horrible (both hardware and software for Windows). The software is absolutely atrocious and actually sends frequency values 100 times smaller than it should.
Yeah; I find almost universally that hardware manufacturers make terrible software - both embedded and PC.
The frequency values one I can easily understand - the serial protocol works in centiHertz, so maybe the PC software just forgets to account for that.
In response to this I've started making a very simple program with the very basics. I plan to add sweep and counter options later. It is already working much better than the original software. Not sure if I will add the waveform upload thingy.
My question is: does anyone know if there is a serial command for enabling and disabling the channel outputs? Also I can only query values from the main channel. Haven't found a way to get values from the second channel. I was planning to make the program sync with the hardware so that it showed the actual settings as soon as the program started but this is making it impossible to implement for both channels.
I too have been working on some control software, though mine is a support library for some more universal control program. I don't want to control just this siggen - I have plans to go much further more generically.
For now, what might be of interest to you is the serial protocol support in my module, which lives at
https://metacpan.org/pod/Electronics::SigGen::FY3200 (for source code view see the "Source" link in the left panel)
That doesn't (yet) have control of the frequency counter or sweep modes, but it does have as much of the main signal generator control as I could work out. In particular it doesn't do phase of channel 1, and it doesn't have output on/off control at all.
Next time I have the thing out, I may try brute-force guessing all possibly bytes of c{BYTE} and c{BYTE}0 to see if there's anything that might turn off a channel, but that technique aside I can't think of any other way we'd find it.
That's awesome! Much bigger scope than mine, that's for sure. I will try to keep mine as small and simple as possible.
The centiHertz thing is what tipped me over, its just too bad. My version is handling that correctly.
What is weird about the phase on channel 1 is that it can be set using the hardware interface but not via the serial interface!
Seems they just couldn't bother adding a few extra lines of code. Lazy!
I might also try guessing commands that have'nt been documented. I'll let you know if I find anything new.
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Tomas, your PC interface software looks good. I hope you're able to discover and implement all the commands.
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Software for Feeltech function generator FY32XX
Here I introduce an alternative software for the function generator Feeltech FX32XX. I did not really like the device software, so this version.
The software works on all systems that have NetFramework version 4.0 or higher installed. The settings are made using the mouse (mouse buttons or mouse wheel) or the keyboard.
Note: This release is a pre-release version that may still have errors. In addition, the wave editor and the online help are not yet integrated.
The software is free (Donationware) and can be used freely. If problems or questions arise, I am gladly available for further inquiries (please use the contact function in the program).
If you are interested in translating for other languages (preferably French, Italian or Spanish), please feel free to contact me.
download:
https://ln.sync.com/dl/86ca78b20/rg7kuefm-naer7kry-n7ctz3ut-qxj6q5tq (https://ln.sync.com/dl/86ca78b20/rg7kuefm-naer7kry-n7ctz3ut-qxj6q5tq)
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Welcome to the forum, Mike. This looks really cool. Have you been lurking in the shadows waiting to make a big splash for your first post? I think you succeeded. Looking forward to trying it out.
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Hi Bitseeker,
thank you for your welcome.
The background for my post was rather the fact that I was not satisfied with the standard software. In addition, I have also integrated a new power supply with an optically isolated USB interface (presentation will take place shortly). For this I needed a different software, because the supplied driver (CH340) could not be used anymore (I used an ADUM 3160 and an FT232RL as interface module).
Greetings from Germany
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Hi Mike,
I have had a quick trial of your s/w, to talk to my Feeltech FY3200S, unfortunately it it seems unable to communicate with it. On plugging the USB cable into the generator my PC 'device' list shows a COM3 Prolific USB to Serial Comm Port which states '' A device which does not exist is specified''. I note also your s/w Settings only shows a COM 1 as a choice. My PC is running Win 10 latest release. Do you have any suggestions that might help?
John
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Hi John,
the serial interface settings only show ports that have been cleared and initialized.
Did you install the driver (CH340)? It should be displayed as interface namely: USB-Serial CH340 (COM?).
Please check if the driver was installed correctly (I think the entry Prolific USB is not from the Feeltech).
Mike
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Hi Mike,
Yes I did try to install (CH340), which stated it was pre-loaded and successful, but unfortunately as soon as I plugged in the USB cable Win 10 reloaded the Prolific USB which I had previously uninstalled/deleted. Incidentally the Prolific USB driver only arrived as an update via Win 10 on plugging the USB cable into the Feeeltech for the first time. Obviously a mistake. I will keep trying when I have some more time but Win 10 has a mind of it's own! :phew: Thanks for responding as it does confirm it really should work.
John
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Hi John,
please look at this video: https://www.youtube.com/watch?v=aWquKi_e-3A (https://www.youtube.com/watch?v=aWquKi_e-3A).
Maybe this will help to solve your problem
Mike
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Hi Mike,
Thanks for that Mike. Yes that solved the communication to the Feeltech as the earlier version of the Prolific driver works partially OK. Your program startup sequence is still unhappy with the driver (no tick) but Com3 now exists and changing the waveform data etc from the PC screen does work OK to the Feeltech. However manual changes on the Feeltech are not reflected to the PC screen. I am presuming this is due to there still being a problem with the driver?
John
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Hi John,
Your program startup sequence is still unhappy with the driver
the program checks at startup whether the driver FT232RL or CH340 is present. If this is the case, the driver found is used. If none of the drivers is found, all found serial ports are checked. If the Feeltech is found at one of these ports, it will be used.
However manual changes on the Feeltech are not reflected to the PC screen
Here you touch a sore point of the concept. The Feeltech does not send any information to the PC during manual changes. In addition, I have found no way to query certain settings of the generator (there are simply no corresponding commands here). I contacted the manufacturer some time ago to question this, but so far have not received an answer.
That's why I decided to integrate presets. This makes it possible to synchronize the generator and the software at program start (see settings in configuration) or manually. To load the presets, press the Button "Presets". To save presets, you must first make the appropriate settings in the displays. Then press the "Preset-Button" for at least 4 seconds and the preset values are saved.
Mike
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Guys : Here is my version of control software for this device. It is for MacOS and is written in Swift 4.2.
Protocol docs are in project. commands really simple, sweep et al. are supported. Will also upload arbitrary wafeforns for 1024 or 2048 sample waveforms.
Enjoy!
https://github.com/kpishere/mhs52xxA (https://github.com/kpishere/mhs52xxA)
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Hi! Someone has found a way to update the firmware? I have a 2.0 version...
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Is there any way to load a particular waveform on start up?
Alexander.
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Hello,
for my scope tests I made this tool, I will try to improve for other waveforms.
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Hello,
I have seen that some of us have developped a control program for the Feeltech FY3200 generator.
This is also something that I have done in VB .NET for Windows, as I was not so satisfied with the program provided by Feeltech.
My program supports remote controlling of CH1/CH2 and internal memories. It is also able to upload custom arbitrary waveforms.
I am glad to share it to the community. You can download it following this link :
https://drive.google.com/drive/folders/1hqqHqvfk1FKhzYSjJ-S6_SUTr_zx0fhp?usp=sharing (https://drive.google.com/drive/folders/1hqqHqvfk1FKhzYSjJ-S6_SUTr_zx0fhp?usp=sharing)
The ZIP file behind the link above contains a PDF document with all needed instructions.
Greetings,
Yves
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Yves,
A quick technical question about your software. When I use it directly connected via USB there is no issue and it all seems to work fine.
I am trying to replace the USB with a Bluetooth connection (HC-05 bluetooth module) in the Feeltech unit that, when paired, looks like a com port on the Windows computer. When an application on the PC tries to connect to the COM port the paired BT connection starts up and establishes a serial link to the device. At the BT receiver you can see that a blinking LED transitions to steady ON when this happens.
If I connect to the FY3224S using a terminal program I can send protocol commands (like bw[n]) and the unit responds on the display with a changed wave form. When I use your software and open the com port it sends 'a' but then reports that there is no device attached. Do you know what might be the problem or if there is something I can do to work out what the issue may be?
Marco
UPDATE: I have got this working but I have to ignore all the error messages from the application. I set ComPortAutoOpen and StartWithoutConnexion to be enabled. This generates the error messages on startup about the bad port but works when I then set parameters. I suspect that the BT startup delay is not tolerated by the software - is that probable? If you can make the source code available I can test what is going on and correct this.
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Hi Marco,
Your suspicions are likely right... I did not figure out that someone could connect the appliance otherwise than with a cable, so I hardcoded the delay of the COM port to 1200 milliseconds ;) Very probably this timeout is too short when connecting via your BT device.
I introduced two new timeout parameters (in GeneralParameters.txt file), which I gave the default value 1200
- ComPortReadTimeout=1200
- ComPortWriteTimeout=1200
By changing this to other larger values, the situation will probalbly be solved.
Just download the new program by using the same link I gave on september 2. I also attached the source code in the new download, should you need to modify something else.
Greetings,
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Thanks for the source code.
The timeouts did not fix the problem but I managed to change the OpenComPort Try/Catch statement so that it at least works on my setup. For the record the changed code is below.
What seems to happen is that the FY unit does not respond to the 'a' message when it is on BT (this works on on cable). The mod to the code avoids the software thinking it is in error, but it is probably not recommended for wider implementation.
Try
' Configure COM port parameters
sp.PortName = comPortName
sp.BaudRate = 9600
sp.Parity = Parity.None
sp.DataBits = 8
sp.StopBits = StopBits.One
sp.NewLine = vbLf
sp.ReadTimeout = prmComPortReadTimeout
sp.WriteTimeout = prmComPortWriteTimeout
' Check if Feeltech 32xx is answering on the selected port
sp.Open()
SendFeeltech("a")
answerFromFY32 = sp.ReadLine
Catch ex As Exception
answerFromFY32 = "Unknown"
Finally
LBMainStatusInfo.Text = answerFromFY32 & " on " & comPortName & " - Buffers (R/W) : " & sp.ReadBufferSize.ToString & "/" & sp.WriteBufferSize.ToString
LBMainStatusInfo.ForeColor = Color.Green
' Connection is OK -> Show the tabs
TABTabControl.Visible = True
If prmShowTestTab <> True Then
' Do not show test tab if configured so
TABTabControl.TabPages.RemoveAt(4)
End If
End Try
Anyway, thanks for the code and the quick response.
Marco
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Hi Yves,
I have the model FY6600 ,I did try it with your software but no luck , would it be possible to put the FY6600 serial command set into the software you created ?
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What seems to happen is that the FY unit does not respond to the 'a' message when it is on BT (this works on on cable). The mod to the code avoids the software thinking it is in error, but it is probably not recommended for wider implementation.
Hi Marco,
Thanks for keeping me posted.
The 'a' command is the only way I have found to check the connectivity, as the feeltech is supposed to answer by returning the model name. Perhaps the BT connexion does not support this two way communication.
As you said, it is probably not a good idea to remove/bypass connectivity check.
But, OK, if you are satisfied with the modification you have done, all is well that ends well.
I have the model FY6600 ,I did try it with your software but no luck , would it be possible to put the FY6600 serial command set into the software you created ?
Hello soundtec,
I would like to please you, but I do not think it would be reasonnable to try to adapt the software for a FY6600.
This has been wrote in a kind of quick and dirty way, just to cover my needs regarding the device I own.
FY32 and FY66 are quite different, so that's not only about replacing the serial commands. For instance, FY66 has the ability to sweep voltage and frequency while FY32 is limited to frequency sweep. So there is nothing in the GUI which I can recuperate to implement the extra commands needed for the FY66.
Another issue is that, due to the poorly documentation provided by the chineese manufacturer, a lot of programing requires discovering how it works by trial and error and/or reverse engineering (This said, the FY66 documentation looks better than those of the FY32). As a consequence, it is nearly mandatory to have a device available to develop/test; which is not my case.
But, who knows, perhaps I will buy one FY66 and develop a new software for it...
I see there is also another group on this blog which aim to improve the FY66. Perhaps you can find what you are looking for there :
- https://github.com/DerKammi/FY6600-15-30-50-60M (https://github.com/DerKammi/FY6600-15-30-50-60M)
- https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/ (https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/)
Wish you the best.
Yves
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Thanks Yves,
Yes Ive been contributing to the FY6600 page from way back ,
Its become such a gigantic amount of information Ive forgotten bits along the way ,
There is another link page here on the Fy6600 Im sure you will like if you havent found it already ,
https://www.eevblog.com/forum/rf-microwave/multiband-wspr-on-the-cheap/msg2352564/#msg2352564 (https://www.eevblog.com/forum/rf-microwave/multiband-wspr-on-the-cheap/msg2352564/#msg2352564)
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Sorry to refresh this old thread but I think this is the correct place to write this request.
I've got a Feeltech FY3224S and I need to realign a late 50's AM tube radio receiver. This unit lacks AM modulation AFAIK. I wonder if there's a way to AM modulate one channel set to the receiver's IF frequency with the other channel set to a, say, 1KHz audio tone. I suppose I'll need some kind of AM modulator circuit for this.
Is it possible?
Any ideas on how to do it?
It seems the newer units like the FY6900 can do this. I'm not 100% positive as I have not read anything about this, but I rather keep my old FY3224S and make a modulating circuit for it if it is feasible.
Thanks a lot in advance.
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You could perhaps import the mathematically calculated values as a custom waveform, in CSV format? Ive never done that personally but maybe somebody here has. I would try it, why not?
It does have some custom waveforms, One may be an AM modulated carrier. It looks a bit like a DSB-modulated carrier, but I remember it had some issues.
My Feeltech is upstairs in a broiling attic and I should bring it downstairs.
This may have been discussed in this thread a long time ago.
Another alternative might be to use its signal and modulate it externally perhaps with a unity gain amplifier you modulate with its own B channel? (that is what they should have implemented, but didn't, but for the money, i'm not complaining. )
Maybe in your junk box you have a suitable device you could use? When I was a kid I made a balanced ring modulator.
Here is a simple circuit to modulate a carrier with a second signal.
https://www.engineersgarage.com/circuit_design/circuit-design-how-to-make-an-amplitude-modulated-wave/ (https://www.engineersgarage.com/circuit_design/circuit-design-how-to-make-an-amplitude-modulated-wave/)
using an n-channel FET.
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You could perhaps import the mathematically calculated values as a custom waveform, in CSV format? Ive never done that personally but maybe somebody here has. I would try it, why not?
I have no idea how to do that :-[
Here is a simple circuit to modulate a carrier with a second signal.
https://www.engineersgarage.com/circuit_design/circuit-design-how-to-make-an-amplitude-modulated-wave/ (https://www.engineersgarage.com/circuit_design/circuit-design-how-to-make-an-amplitude-modulated-wave/)
using an n-channel FET.
Interesting!
In think that circuit may deliver much more signal than needed (for IF tuning) when it is injected enough signal to make the FET work but I suppose I can put a voltage divider (i.e.: portentiometer) in the output.
Thanks a lot!
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Cant you just estimate it, ear out the adjustment?
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There are litteraly 2 small caps: one from neutral to the output and one from the life to the the output. These 2 caps form a capacitive divider and thus one see's half the voltage. For safety reasons these caps are Y-rates types that a guarantied not to fail short. Usual capacitance is about 4.7 nF.
In principle a transformer power supply will show a similar voltage. Here it is from capacitive coupling in the transformer. However the capacitance is usually much smaller (e.g. maybe 1%) than the Y-caps. A linear supply does not need the extra caps because there are essential not RF emissions. Even a SMPS behind the conventional transformer can usually get away without.
PE is the short for protective earth, so the safty ground from the 3 rd. pin. If available one could have the capacitors from L to PE and N to PE and than either a direct connection from PE to the BNC or just a capacitor.
I opted for adding a 30VA isolation transformer (Conrad), but I added no PE to the mains connection, so everything is still floating. I prefer to keep it floating, if I can.
I tested the voltages from BNC ground to mains ground, I see 45V AC and 6 µA AC. So the current value is quite okay, but the 45V still worries me (a bit). Do I have options to reduce it apart from adding PE ground to the box? Could I safely remove (or decrease value) of those two capacitors? And even then, won't that just lower the current further (but not the voltage)? Am I doing this right?
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[attach=1]
Sorry to refresh this old thread but I think this is the correct place to write this request.
I've got a Feeltech FY3224S and I need to realign a late 50's AM tube radio receiver. This unit lacks AM modulation AFAIK. I wonder if there's a way to AM modulate one channel set to the receiver's IF frequency with the other channel set to a, say, 1KHz audio tone. I suppose I'll need some kind of AM modulator circuit for this.
Is it possible?
Any ideas on how to do it?
It seems the newer units like the FY6900 can do this. I'm not 100% positive as I have not read anything about this, but I rather keep my old FY3224S and make a modulating circuit for it if it is feasible.
Thanks a lot in advance.
This page says you can do AM modulation with a single FET:
https://www.engineersgarage.com/circuit_design/circuit-design-how-to-make-an-amplitude-modulated-wave/ (https://www.engineersgarage.com/circuit_design/circuit-design-how-to-make-an-amplitude-modulated-wave/)
[attach=1]
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Very interesting. Thanks! :-+
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I have seen that some of us have developped a control program for the Feeltech FY3200 generator.
Hi, YvesMalherbe,
Thank you, great program. Can you ask for a couple of improvements?
1. Make the same settings and presets for the second channel.
2. In presets, add the ability to change the frequency after a certain time, for example:
preset 1:
100 Hz - 5 minutes
2000 Hz - 20 minutes
3000 Hz - 2 minutes
... 10-20-30 different frequencies
and loop this work. There are an unlimited number of presets, but only the selected one works. That would be amazing :-+ Thank you!
Good luck! Elwood
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For controlling the FeelTech in complex ways, there's a Python library which is easy to use:
https://github.com/atx/python-feeltech
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Has anyone noticed the FY3224S can go up to 2^32Hz (about 40MHz)?
A bug in the firmware allows this to be set on the unit when sweeping, but the fixed frequency can be changed via USB (fytool if you change the max)
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Hello Elwood,
Glad to hear that my software helps you.
I have seen that some of us have developped a control program for the Feeltech FY3200 generator.
Thank you, great program. Can you ask for a couple of improvements?
1. Make the same settings and presets for the second channel.
2. In presets, add the ability to change the frequency after a certain time.
I will have a look to your requests, but don't expect a fast reply, as I am currently quite busy on other things professionnally.
Regards,
Yves
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Is there any way to either use the FY3224S with an external 10 MHz reference, or calibrate it to improve the frequency accuracy?
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Sorry to revive an old topic but my FY3224S just developed an issue. Somehow the sine wave is no longer working. It outputs absolutely nothing when the sine wave is selected, neither CH1 nor CH2. All the other waves work OK, even ARB1 which is indeed a sine wave.
I have already tried the "reset" explained previuosly in this very topic:
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1175563/#msg1175563 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1175563/#msg1175563)
...unfortunately to no avail. Any Ideas?... anything I could do to restore the native sine wave?
Thanls a lot in advance.
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Please help I have just started learning about fy3224 dds.
I tried several things, including PC connection, everything worked.
The sinus signal of ch1 and ch2 changed unexpectedly.
I don't know what happened and how to fix it?
Does it have factory reset?
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You might try the "reset" procedure mentioned in the message by Calambres just before yours.
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I keep investigating this strange and sudden behaviour. Somehow now CH2 displays a "somewhat" sinusoidal wave that do not correspond to the paramaters given, neither frequency nor amplitude. CH1 still no SINE wave but a 213mV DC offset. I cannot understand why SINE is not working but ALL other waves work perfectly OK. What's different in SINE to the others?
I've opened the case and found nothing apparently wrong there. Also extracted the generator panel and all seems OK. No bulging or leaking capacitors, no overheating components, no open traces, no rusting leads, no nothing!
I'm amazed to see that my FY3200S is not the only one developing these sympthoms ::) The "reset" I mentioned before is not a real reset but a frequency calibration mode. The other working waves are spot on in frequency... wish I knew of a real reset mode.
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I give up!
I, for the life of me, cannot see any physical problems anywhere. I strongly suspect it's a data corruption of some sort. Nobody knows of a REAL reset for this AWG?
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This thing is driving me nuts!
It has developed another annoying sympthom: the selected frequency is increased by no less than a 43% |O
100Hz selected -> 143.050Hz measured
10KHz selected -> 14.3050KHz measured
100KHz selected -> 143.050KHz measured
The measures are made with a DSO scope and an external freq. counter. At least, the increasings are consistent!
On the other hand, if I read the counts with the FY3224S' own counter, the readings correspond with what I selected, i.e.: 100Hz reads 100Hz, etc.
No idea what is happening here but still I wish I had a way to reset this thing ::) (SINE wave is still not working at all)
Of course, the frequency calibration routine (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg1175563/#msg1175563) I cited above works well and brings it back to normal. now 100Hz really is 100Hz, etc, but I have no idea whay it suddenly changed by such a great percentage.
[EDIT] It seems to be related to a FW bug regarding the sweep function. I used that function a couple of days ago... ::)
[EDIT2] Added a Feeltech official document on this procedure I got from somewhere...
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I know I'm a little late to the party, but the FY3224S is still being sold and is still the cheapest 2 channel AWG available as far as I know.
I got it yesterday.
Board version: 3.2
PSU version: 1.32
Firmware version: 4.1
So far everything works.
But I have some jitter at the square wave.
Strangely not at 6MHz, but for example at 5MHz and around.
I see two vertical traces (See fy3200s_5MHz_sqr.jpg).
Is this a known problem or is my device faulty?
There is also a possibility that it is partly due to the cheap Zeeweii DSO2512G, but normally it is still stable in these frequency ranges.
Does anyone know this phenomenon?
Thank you!
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I'll answer my own question:
here (https://www.dalbert.net/?p=322#attachment_328) you can see that it is not due to the oscilloscope. This jitter seems to be typical for the FY3200S.
The images there look partly worse than on my device.
Especially 5V/5MHz looks more like a square wave on my version. There was apparently a small improvement.
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So far everything works.
But I have some jitter at the square wave.
Strangely not at 6MHz, but for example at 5MHz and around.
I see two vertical traces (See fy3200s_5MHz_sqr.jpg).
Does anyone know this phenomenon?
This reminds me irresistibly of the Fourier series of a square signal. The frequency of the oscillator is fixed at 24 MHz, and the final signal is probably the sum of a series of sine waves with frequencies, multiples of which is 24 kHz. It will therefore be much more difficult to fit a 5MHz square wave than a 6MHz square wave into series of 6MHz, 12MHz, 18MHz and 24MHz.
See https://en.wikipedia.org/wiki/Fourier_series (https://en.wikipedia.org/wiki/Fourier_series)
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This reminds me irresistibly of the Fourier series of a square signal. The frequency of the oscillator is fixed at 24 MHz, and the final signal is probably the sum of a series of sine waves with frequencies, multiples of which is 24 kHz. It will therefore be much more difficult to fit a 5MHz square wave than a 6MHz square wave into series of 6MHz, 12MHz, 18MHz and 24MHz.
Yes.
The good thing is that there are "sweet spots" at certain frequencies (multiples).
With an appropriate waveform, the device can also generate stable 36MHz or 48 MHz, which is twice the specified bandwidth.
Not particularly nice (forget the amplitude), but stable.
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I know the FY3200s isn't the latest and greatest anymore, but it's still the cheapest AWG and it's not that bad.
However, the user interface is a bit annoying.
Fortunately, you can control the device remotely with a PC.
Since I couldn't find a GUI application that also runs on Linux and Raspberry Pi 4, I wrote one myself.
I have added function to function and now I'm almost finished. ;-)
Features are (besides the obvious).
- 50Ohm load resistor mode
- Attenuator mode (dB)
- Amplitude limitation for sensitive devices (e.g. TinySA).
- Amplitude correction table (for adjusting e.g. oscilloscopes).
- Display of Vrms for standard waveforms and dBm at 50 ohms.
- Software sweep with amplitude sweep.
- Unlimited named presets.
. Waveform upload (15 seconds)
- Waveform conversion from bitmaps (PNG etc.) with single and double scan for fun shapes.
I still have some tweaking to do.
When it's done I can share the source code if anyone is interested.