FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator

[milamber]

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?

[bobofrut]

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

[cdman]

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

[bobofrut]

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

Thank you so much!

[brainwash]

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.

[cdman]

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.

[Texacate]

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.

[Texacate]

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...

[pascal_sweden]

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

[Texacate]

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. 

[pa3hfu]

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:

[pa3hfu]

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  ;-)

[MikeLogix]

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. 

[Texacate]

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?

[alsetalokin4017]

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.

[Texacate]

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.

[rodelco54]

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

[LogicalDave]

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.

[Texacate]

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)

[pascal_sweden]

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.

[rodelco54]

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.

[Texacate]

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.

[pascal_sweden]

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?

[SteveyG]

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
Use Coupon Code "FY3224S"

[SteveyG]

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.