EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: CharlieWorton on June 14, 2017, 06:47:46 PM

Title: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: CharlieWorton on June 14, 2017, 06:47:46 PM
I was going to buy a cheap Feeltech, but some have reported that its lack of proper grounding is allowing voltages of around 90 volts at 1 milliamp to run through the probes.  Concerns have been raised about connecting it to mpus and such.  So I was kind of resigned to swapping out the internal power supply for something better, which is expensive and bothersome.

Then I came across this thing - an 'RD JDS6600 Series 25MHZ Digital Control, Dual-channel, DDS Function Signal Generator/frequency meter Arbitrary sine Waveform' thingie.

Here's a link to AliExpress:
https://www.aliexpress.com/item/RD-JDS6600-Series-25MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32811781657.html?spm=2114.12010108.1000023.4.2xZidl (https://www.aliexpress.com/item/RD-JDS6600-Series-25MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32811781657.html?spm=2114.12010108.1000023.4.2xZidl)

Let's see what I remember.  A full color LCD display on the front.  Power through a wall wart, so no high voltage transients running around.  Some very nice software that appears to do a lot more than the remote control software for the Feeltech.  A whack of pre-programmed waveforms, most of which have names I don't recognize.  A proper sine wave up to 25Mhz.  And apparently some decent square and triangle waves up to 15Mhz (the feeltech crapped out around 4Mhz).  The ability to store up to 60 different user defined waveforms, as well as sample an incoming wave form.  Dual channel outputs.

There are a ton of specifications on the site.  I won't pretend to know whether they're significant.  I'm hoping you folks do.

They want $140 Canadian including e-packet shipping (which is pretty fast).  The Feeltech was $85, plus whatever I have to do to solve the voltage transient problem.

I have the impression that this thing is somewhere in between the Feeltech cheapie, and a name brand signal generator from Rigol et al.

I'm leaning towards buying one.  I'd sure appreciate feedback from all of you.  Or any of you.

Let me know what you think, Kay?  Thanks, folks - Charlie
Title: Re: Anybody know anything about this signal generator?
Post by: CharlieWorton on June 14, 2017, 07:11:52 PM
Here's kind of a youtube video about the signal generator:

https://www.youtube.com/watch?v=Fn76Yp-vATI#t=179.894071 (https://www.youtube.com/watch?v=Fn76Yp-vATI#t=179.894071)

There's no audio - not even a muzak track - but you get a closeup of the face of the unit being manipulated by what I suspect are Chinese hands.

Sure seems to do a lot.

>Charlie
Title: Re: Anybody know anything about this signal generator?
Post by: CharlieWorton on June 15, 2017, 02:03:27 AM
Well, I guess we'll all find out together!   ;D

I've ordered it from AliExpress, and they'll be shipping via e-packet.  So I should have it in about 3 weeks.

When it shows up, I'll share my experiences here.

Take care, all.  Hope this works!

>Charlie
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pascal_sweden on June 15, 2017, 03:16:51 AM
Nice to hear! I look forward to your review and take it apart video :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: CustomEngineerer on June 15, 2017, 01:07:47 PM
Perhaps you could link him to some of your teardown or review videos to help him better understand what you are asking for.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: CharlieWorton on June 19, 2017, 06:13:14 PM
I've been planning a YouTube channel for about a year - or more - now.  I have a lot of cool DIY projects that center around 3D printing, and a lot more - like a review of the JDS 6600, and an updated review on the Korad power supply - centering around electronics.  With my Wriggle DS1054Z arriving tomorrow, I'll have a decent scope to test them on.  I'm also building a really simple UV contact printer to allow me to make some PCBs.  So there's a lot of topic material there.

Yes, I'll be doing a bit of a teardown on the 6600 when it shows up - at least enough to show people what's in the case - and some decent testing of the signal quality vs frequency.  I'm not expecting a great deal, but i hope that it's better than Feeltech.  I'll be disappointed if it's not.

>Charlie
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: CharlieWorton on June 24, 2017, 11:07:54 AM
I ordered one of these about 10 days ago.  According to Canada Post, they received it a few days ago, but haven't done anything with it.

However, the unit is on sale right now.  I paid $136.86 CAD; the current price is $123.50 CAD, so maybe 10% off or so.  Or a little more; I think their regular price was $140 CAD, but I got a few bucks off for being a nice guy.  Heh, heh. Little do they know.

Anyway, mine hasn't arrived yet, so I can't endorse it.  But for any one who was on the fence about ordering one, you can get it for 10% off right now.

Here's a link:

https://www.aliexpress.com/item/RD-JDS6600-Series-25MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32811781657.html (https://www.aliexpress.com/item/RD-JDS6600-Series-25MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32811781657.html)

It's also worth noting that they've introduced several new models; they now claim a new high frequency of 60Mhz on their most expensive model.  This is for a sine wave.  For square or triangle waves, they claim a maximum of 15Mhz across the board, for all their models.

Here's a link to a page listing all their models:

https://www.aliexpress.com/item/RD-JDS6600-Series-40MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32814611834.html (https://www.aliexpress.com/item/RD-JDS6600-Series-40MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32814611834.html)

I don't believe the 60Mhz claim.  I'm sure there's something there, but I'll bet it winds up looking like a weak, wobbly triangle wave than a pure sine.

Anyway, for someone interested in checking it out... there it is.

>Charlie
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 24, 2017, 04:29:29 PM
Newbie here, but I was ghosting this thread and thought you guys might be interested in my 'first look' at this 25MHz version:

(Yeah, shameless plug)

https://www.youtube.com/watch?v=b66nnWb3z54 (https://www.youtube.com/watch?v=b66nnWb3z54)

It's a bit rough, should have taken a look at the high-frequency performance; but there might still be something in there that's useful for anyone thinking of buying.

If anyone's got any tests that they're specifically interested in I'm happy to see how it performs and post the results here..
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on June 24, 2017, 04:59:23 PM
An FPGA and R2R ladder DAC is rather common for the low cost Fgens.

I would consider 4 points for further tests:

1) Noise, e.g. from the SMPS or just from the DAC: So maybe use just a DC or low amplitude sine.

2) DAC linearity: This can usually be seen from a slow triangle / ramp.

3) Output amplifier slew rate: Many similar low cost generator run in to a slew rate limit with full amplitude and high frequency. So usually the maximum amplitude is reduces at the highers frequency.

4) There are 2 relays per output channel. So this could be an output attenuator. This has good sides, but might also limit the Offset range, when using low amplitudes.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: technogeeky on June 24, 2017, 05:33:00 PM
I bet this device is nearly identical to the MHS-5200A (and higher versions), except that it has the much nicer screen (and perhaps better UI).

Hopefully we'll see a basic teardown soon.

Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 24, 2017, 06:56:25 PM
Quote from: technogeeky
Hopefully we'll see a basic teardown soon.

Here are some high-resolution images that I took of the main boards from my (brief) teardown in the video above:

Top of the main board:
(http://i.imgur.com/3jp9fmQ.jpg)

Base of the screen board:
(http://i.imgur.com/XdCW9lt.jpg)

Bottom of the main board (nothing interesting)
(http://i.imgur.com/LJp5FYY.jpg)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 24, 2017, 07:26:40 PM
Quote from: Kleinstein
An FPGA and R2R ladder DAC is rather common for the low cost Fgens.
Interesting, I've haven't torn down a cheapie Fgen like this before so that explains that.
Quote from: Kleinstein
I would consider 4 points for further tests:

Cheers for the suggestions!

Quote from: Kleinstein
1) Noise, e.g. from the SMPS or just from the DAC: So maybe use just a DC or low amplitude sine.

DC out at 1V, AC coupled, output OFF:

(http://i.imgur.com/f9yb6nL.png)

Same as above, output ON:

(http://i.imgur.com/AqQyAbb.png)

Quote from: Kleinstein
2) DAC linearity: This can usually be seen from a slow triangle / ramp.

Triangle wave, 1KHz, 1Vpp:

(http://i.imgur.com/to3ksQ5.png)

Quote from: Kleinstein
3) Output amplifier slew rate: Many similar low cost generator run in to a slew rate limit with full amplitude and high frequency. So usually the maximum amplitude is reduces at the highers frequency.

Here's a sine wave, 25MHz, set to 1Vpp (but into a 50 Ohm load so what we 'should' see is 500mVpp)

(http://i.imgur.com/larC8Mw.png)

Same as above, but a square wave:

(http://i.imgur.com/fNuACLs.png)

Quote from: Kleinstein
4) There are 2 relays per output channel. So this could be an output attenuator. This has good sides, but might also limit the Offset range, when using low amplitudes.

Looks like you were right about the output attenuators, at 100mVpp setting (into 50 Ohms again), the maximum offset I can set is 0.25V;

(http://i.imgur.com/R6A6wjA.png)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: gedong on June 24, 2017, 11:08:06 PM
I Actually just find out this today while searching for budged DDS gen..

actually they look almost identical..
(http://www.thanksbuyer.com/image/data/deacriptionpic/201706/54043-1.jpg)

One of reviewer said that this model uses Altera FPGA Cyclone IV, but never showed the internal boards..
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: gby on June 24, 2017, 11:27:56 PM
The JDS6600 generator family has very similar functionality to the Feeltech FY3200 and the MHS-5200 generators.  The JDS6600 even uses the exact same plastic case for the enclosure as the FY3200, MHS-5200.  For a comparison of those other generators see:
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg697718/#msg697718 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg697718/#msg697718)

From testing the FY3200 myself and reading on the MHS5200 they both are both limited in their output voltage range into 50 Ohm load without clipping or high distortion.  So the first test I would suggest is:

  1.  Set 10 KHz sinewave with 20 Vpp/maximum amplitude on an oscilloscope with 1 Meg impedance.  Then add the 50 Ohm termination and see if the output drops to 1/2 or if clipping or distortion starts happening.

On these type generators the output buffer is often slew rate limited which in turn means the output amplitude at higher frequencies is limited.  So, the second test I recommend is:

  2.  Set a 10 Vpp 100 kHz sinewave on the output into oscilloscope with 50 Ohm termination.  Then increase the frequency until maximum frequency to see if or at what frequency it starts distorting horribly.

On the FY3200 generator when you change the frequency the output waveform glitches.  Ideally one would expect a change in frequency with a sine wave to step change the slope at the frequency change with no step in the actual voltage.  Unfortunately the FY3200 has steps in the output because the phase as well as the frequency changes when you change the frequency.  So, the third test I would love to see is:

  3.  Set the generator to 5 Vpp, 10 kHz sine wave and then step change the frequency to 20 kHz.  Try to capture on the oscilloscope the moment when the frequency changes.  If you have advanced triggering I set trigger width must be < 20 uSec and then set to capture once.

When you use two channels both outputting the same frequency sine wave with the phase 90 Deg apart it would be great to repeat test 3 to insure that both channels change frequency at the same time and with no glitches.

  4.  Repeat test 3 but with two sine wave channels outputting sine waves with 90 Deg relative phase.

The last requested test is really just a question of functionality.  This generator can do frequency sweeps.  But, can it do frequency sweeps while outputting two wave forms?  Last requested test is:

  5.  Can you set the generator to output 2 sine waves with 90 Deg relative phase and then sweep the frequency such that both channels sweep in frequency and stay in phase lock?

In advance I thank you for any of the above tests that you could do and report back results.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on June 25, 2017, 05:31:43 AM
The triangle waveform looks quite good - better than I remember from the MHS5200. However the scope setting is not that good to tell if the little nonlinearity is from the scope of from the generator. If would need a zoom in on details of the slope and maybe an even lower frequency. Usually a simple R2R DAC would show visible errors near the center or 1/4 of the range. There are 2 pots for each channel so these might be for adjusting at least that largest error.

The picture of the circuit is just to bad in resolution to read the chip numbers. The output amplifiers might be interesting. For the rest I would expect an AD603 or similar for the amplitude adjustment.

Are the USB and TTL I/Os isolated from the normal outputs ? It does not look like.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 25, 2017, 09:26:04 AM
The JDS6600 generator family has very similar functionality to the Feeltech FY3200 and the MHS-5200 generators.  The JDS6600 even uses the exact same plastic case for the enclosure as the FY3200, MHS-5200.  For a comparison of those other generators see:
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg697718/#msg697718 (https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg697718/#msg697718)

Huh, interesting. Thanks for the link!

Quote from: gby
From testing the FY3200 myself and reading on the MHS5200 they both are both limited in their output voltage range into 50 Ohm load without clipping or high distortion.  So the first test I would suggest is:

  1.  Set 10 KHz sinewave with 20 Vpp/maximum amplitude on an oscilloscope with 1 Meg impedance.  Then add the 50 Ohm termination and see if the output drops to 1/2 or if clipping or distortion starts happening.

1 meg impedance, max amplitude @ 10KHz:
(http://i.imgur.com/ZvS67oD.png)

50 Ohm termination:
(http://i.imgur.com/5aukZ8D.png)

Quote from: gby
On these type generators the output buffer is often slew rate limited which in turn means the output amplitude at higher frequencies is limited.  So, the second test I recommend is:

  2.  Set a 10 Vpp 100 kHz sinewave on the output into oscilloscope with 50 Ohm termination.  Then increase the frequency until maximum frequency to see if or at what frequency it starts distorting horribly.

So I think there are 2 interesting points here, at 10MHz and at 25MHz. Because above 10MHz the amplitude is restricted down from 20Vpp to 10Vpp (probably for slew rate reasons).

At the maximum frequency useable at 20Vpp (into 50 Ohms, so we should be seeing 10Vpp):

(http://i.imgur.com/r1J55eY.png)

Looks pretty distorted. Here's an FFT (didn't use specan because I couldn't find my big attenuator :P)

(http://i.imgur.com/7i3F028.png)

So that second harmonic is at about -30dBc, which is out of spec (Spec says -40dBc).

At 25MHz, it looks a bit cleaner (but the amplitude is now 10Vpp out, which should look like 5Vpp into 50 Ohms):

(http://i.imgur.com/BArqsY7.png)

And an FFT:

(http://i.imgur.com/mIDOSiU.png)

Looks to be about -40dBc, so that's roughly in spec.

Quote from: gby
On the FY3200 generator when you change the frequency the output waveform glitches.  Ideally one would expect a change in frequency with a sine wave to step change the slope at the frequency change with no step in the actual voltage.  Unfortunately the FY3200 has steps in the output because the phase as well as the frequency changes when you change the frequency.  So, the third test I would love to see is:

  3.  Set the generator to 5 Vpp, 10 kHz sine wave and then step change the frequency to 20 kHz.  Try to capture on the oscilloscope the moment when the frequency changes.  If you have advanced triggering I set trigger width must be < 20 uSec and then set to capture once.

Here's what that looks like:
(http://i.imgur.com/CMMyP74.png)

Slightly zoomed in:
(http://i.imgur.com/bwh9I3C.png)

Quote from: gby
When you use two channels both outputting the same frequency sine wave with the phase 90 Deg apart it would be great to repeat test 3 to insure that both channels change frequency at the same time and with no glitches.

  4.  Repeat test 3 but with two sine wave channels outputting sine waves with 90 Deg relative phase.

I couldn't find a way to change the frequency of both channels at once, so I'm not sure if that's possible. Here's what 2 channels at 90 deg phase shift look like when channel 1 is increased in frequency:

(http://i.imgur.com/NNJwUkp.png)

Quote from: gby
The last requested test is really just a question of functionality.  This generator can do frequency sweeps.  But, can it do frequency sweeps while outputting two wave forms?  Last requested test is:

  5.  Can you set the generator to output 2 sine waves with 90 Deg relative phase and then sweep the frequency such that both channels sweep in frequency and stay in phase lock?

In advance I thank you for any of the above tests that you could do and report back results.

As far as I can tell it's not possible to do sweeps on 2 channels at once.

Cheers for your suggestions!
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 25, 2017, 09:48:09 AM
Quote from: Kleinstein
The triangle waveform looks quite good - better than I remember from the MHS5200. However the scope setting is not that good to tell if the little nonlinearity is from the scope of from the generator. If would need a zoom in on details of the slope and maybe an even lower frequency. Usually a simple R2R DAC would show visible errors near the center or 1/4 of the range. There are 2 pots for each channel so these might be for adjusting at least that largest error.

All good points, if I get some time later I might try a super-low frequency and use the datalogging feature on my keysight DMM to get some more precise measurments of that.

Quote from: Kleinstein
The picture of the circuit is just to bad in resolution to read the chip numbers. The output amplifiers might be interesting. For the rest I would expect an AD603 or similar for the amplitude adjustment.

Strange, I can read most of the chip numbers except a couple on the left - if you go to the raw link it should be a higher resolution than what you're seeing on the forum.

From left-to-right with the front end it looks like a bunch of discretes and then (same for both channels):
1. An AD8056A 300MHz voltage feedback amp.
2. An AD835 250MHz 4-quadrant multiplier.
3. An AD8017 160MHz high output drive op amp
4. All the relays & discretes as well as:
5. A TI part, 3001I. I'm assuming this is the THS3001, which is a 420MHz current-feedback amplifier.

Quote from: Kleinstein
Are the USB and TTL I/Os isolated from the normal outputs ? It does not look like.

The chip between the FPGA and TTL I/Os is just a 74HC14 hex inverter, so probably not.

I haven't been able to identify the chip between the FPGA and the USB port, the code looks like CR3400
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: onlooker on June 25, 2017, 10:41:51 AM
That is the "well known" WCH CH340G.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: gby on June 25, 2017, 10:43:19 PM
vk2seb,

Thanks for your testing on my questions:

  1.  Looks like they got the output buffer "strength" right this time.  The MHS-5200 had too small a power supply voltage to reach full 10 Vpp across 50 Ohm and the FY3200 buffer had to low a current limit.  So, the JDS66000 is definitely improved here and from your photograph it looks like a reasonable heat sink.  :-+

  2.  Looks like some slew limiting on the output at 10 MHz but not too bad.  The official specs say 20 Vpp up to 10 MHz, 10 Vpp 10 - 30 MHz, and 5 Vpp > 30 MHz.  These specs imply a slew limit of just better than 5V0-p*2*pi*30MHz = 942 V/uSec.  Probably around 1000 V/uSec which is pretty good.

  3. Changing single channel frequency looks to be smooth which is good.   :-+

  4.  For changing the frequency when both channels are running the same frequency you say:
    "I couldn't find a way to change the frequency of both channels at once, so I'm not sure if that's possible"
These generators usually have a channel synchronization mode where you lock them such than changing one channel parameter changes both channels.  In the JDS66000 manual I found on line it says under the system setting menu:

4.4.2 Sync: When sync, CH1 is the object of operation. CH2 parameter will be changed with the changes of CH1 parameter. When the sync item is selected, you can press  or knob to select the sync item needed, press ON softkey to select and press OFF softkey to cancel.

Could you check for the system setting sync function and try changing the frequency of two channels locked at 90 Deg phase again?

  5.  Perhaps with the two channels sync'ed you can then sweep two channels with a phase difference simultaneously??  One can only hope....

Again, thanks for your help in evaluating this generator and sharing.

gby
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on June 26, 2017, 12:07:32 AM
The parts used seem to be a little more expensive (e.g. AD835 instead of lower cost AD603)  than those in the super cheap versions. The amplifiers also look rather fast. Still strange that there are additional AD8017.

I finally found the higher resolution pictures. So I got a look at the DAC: they seem to use 15 lines in a thermometer style to get the upper about 4 Bits with less errors / glitches. So the DAC is not just an R2R ladder.
Title: Re: Anybody know anything about this signal generator?
Post by: RD Tech on June 26, 2017, 03:44:17 PM
Here's kind of a youtube video about the signal generator:

https://www.youtube.com/watch?v=Fn76Yp-vATI#t=179.894071 (https://www.youtube.com/watch?v=Fn76Yp-vATI#t=179.894071)

There's no audio - not even a muzak track - but you get a closeup of the face of the unit being manipulated by what I suspect are Chinese hands.

Sure seems to do a lot.

>Charlie
sorry, because the english is not good, so we just show the operation and test result . I guss those don't affect our product ..
Title: Re: Anybody know anything about this signal generator?
Post by: RD Tech on June 26, 2017, 03:47:29 PM
Well, I guess we'll all find out together!   ;D

I've ordered it from AliExpress, and they'll be shipping via e-packet.  So I should have it in about 3 weeks.

When it shows up, I'll share my experiences here.

Take care, all.  Hope this works!

>Charlie
we use the different shipping way for different country. most coutry are free shipping , fast and safty
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 26, 2017, 03:49:52 PM
very good, you also check our youtube video https://www.youtube.com/watch?v=Fn76Yp-vATI&t=237s (https://www.youtube.com/watch?v=Fn76Yp-vATI&t=237s)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 26, 2017, 03:56:31 PM
I ordered one of these about 10 days ago.  According to Canada Post, they received it a few days ago, but haven't done anything with it.

However, the unit is on sale right now.  I paid $136.86 CAD; the current price is $123.50 CAD, so maybe 10% off or so.  Or a little more; I think their regular price was $140 CAD, but I got a few bucks off for being a nice guy.  Heh, heh. Little do they know.

Anyway, mine hasn't arrived yet, so I can't endorse it.  But for any one who was on the fence about ordering one, you can get it for 10% off right now.

Here's a link:

https://www.aliexpress.com/item/RD-JDS6600-Series-25MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32811781657.html (https://www.aliexpress.com/item/RD-JDS6600-Series-25MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32811781657.html)

It's also worth noting that they've introduced several new models; they now claim a new high frequency of 60Mhz on their most expensive model.  This is for a sine wave.  For square or triangle waves, they claim a maximum of 15Mhz across the board, for all their models.

Here's a link to a page listing all their models:

https://www.aliexpress.com/item/RD-JDS6600-Series-40MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32814611834.html (https://www.aliexpress.com/item/RD-JDS6600-Series-40MHZ-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter-Arbitrary-sine/32814611834.html)

I don't believe the 60Mhz claim.  I'm sure there's something there, but I'll bet it winds up looking like a weak, wobbly triangle wave than a pure sine.

Anyway, for someone interested in checking it out... there it is.

>Charlie
because we update our JDS6600. now 15MHz, 30MHz, 50Mhz, 60mhz are new version, there is not any problem for this data, we never sell fake data products,
quality is very importanct as our life, you can asy"you don't believe" , but our data is real, only you test it , you have right to say those words, ok?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 26, 2017, 04:00:24 PM
I bet this device is nearly identical to the MHS-5200A (and higher versions), except that it has the much nicer screen (and perhaps better UI).

Hopefully we'll see a basic teardown soon.
you are right , they are from same designer, but for JSD6600, our DPS engineer also join in to design this ,. so this JSD660 is better than MHS may many times
so you check
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 26, 2017, 04:32:21 PM
The parts used seem to be a little more expensive (e.g. AD835 instead of lower cost AD603)  than those in the super cheap versions. The amplifiers also look rather fast. Still strange that there are additional AD8017.

I finally found the higher resolution pictures. So I got a look at the DAC: they seem to use 15 lines in a thermometer style to get the upper about 4 Bits with less errors / glitches. So the DAC is not just an R2R ladder.
you should know quality decide the price ...
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: acastlenut on June 26, 2017, 06:25:26 PM
I received my JDS6600/25Mhz about a week ago and I am suitably impressed with its functionality. I have put it through some tests on a Siglent SDS 2204X 200Mhz DSO and it performs rather well. The two exceptions are a)  the power pack leaks 78 V AC measured from mains earth to the DC ground of the power pack. Leakage current is 14µA. Not life threatening and can be fixed by replacing it with a transformer based PS. b) Both BNC connector cables have a very intermittent and tenuous connection when plugged into the generator. Sometimes I cannot get a solid signal without putting side tension on the leads.
To vk2seb, I enjoyed your presentation video and noted the relay click noise was masked by the incessant transducer beep. There is a way to turn of the beep and save that setting so it never sounds unless you turn it on again. Also QBY's question regarding both channels syncing. As far as can see the SYS button lets you set the frequency, waveform, amplitude, offset and duty to track (sync) chan 1 and chan 2. This is also true in the software which drives the JDS6600 through the USB port. Altogether a nice piece of kit.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 26, 2017, 06:42:29 PM
Quote from: gby
  4.  For changing the frequency when both channels are running the same frequency you say:
    "I couldn't find a way to change the frequency of both channels at once, so I'm not sure if that's possible"
These generators usually have a channel synchronization mode where you lock them such than changing one channel parameter changes both channels.  In the JDS66000 manual I found on line it says under the system setting menu:

4.4.2 Sync: When sync, CH1 is the object of operation. CH2 parameter will be changed with the changes of CH1 parameter. When the sync item is selected, you can press  or knob to select the sync item needed, press ON softkey to select and press OFF softkey to cancel.

Could you check for the system setting sync function and try changing the frequency of two channels locked at 90 Deg phase again?

You're dead right, a case of 'RTFM, vk2seb' ;).

Here's what that looks like 10KHz->20KHz, 90 deg phase lock, 5Vpp:

(http://i.imgur.com/nFfsSME.png)

So yeah, channel 2 is definitely not behaving there.

Quote from: gby
  5.  Perhaps with the two channels sync'ed you can then sweep two channels with a phase difference simultaneously??  One can only hope....

Good news: You can indeed sweep the 2 channels simultaneously.
Bad news: They don't stay in phase lock.

With a 0 deg phase set (sweeping 10KHz->20KHz):
(http://i.imgur.com/zNuMfLQ.png)

With a 90 deg phase set (sweeping 10KHz->20KHz):
(http://i.imgur.com/0VNpzz4.png)

Difficult to get a capture of the whole sweep without nothing meaningful being visible.

Quote from: gby
Again, thanks for your help in evaluating this generator and sharing.

No worries at all!
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 26, 2017, 06:48:10 PM
Quote from: acastlenut
The two exceptions are a)  the power pack leaks 78 V AC measured from mains earth to the DC ground of the power pack. Leakage current is 14µA. Not life threatening and can be fixed by replacing it with a transformer based PS. b) Both BNC connector cables have a very intermittent and tenuous connection when plugged into the generator. Sometimes I cannot get a solid signal without putting side tension on the leads.

Ooft, nice find on the mains leakage. I haven't been able to break my BNC connection by wobbling it around a fair bit (just tried), maybe luck of the draw? :/

Quote from: acastlenut
To vk2seb, I enjoyed your presentation video and noted the relay click noise was masked by the incessant transducer beep. There is a way to turn of the beep and save that setting so it never sounds unless you turn it on again. Also QBY's question regarding both channels syncing. As far as can see the SYS button lets you set the frequency, waveform, amplitude, offset and duty to track (sync) chan 1 and chan 2. This is also true in the software which drives the JDS6600 through the USB port. Altogether a nice piece of kit.

Glad you enjoyed it! Good point on the annoying transducer beep, I'm definitely going to try that. You're right about the channel synchronization, I didn't RTFM ;)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 27, 2017, 04:31:43 PM
Quote from: Kleinstein
An FPGA and R2R ladder DAC is rather common for the low cost Fgens.
Interesting, I've haven't torn down a cheapie Fgen like this before so that explains that.
Quote from: Kleinstein
I would consider 4 points for further tests:

Cheers for the suggestions!
what you test ? JDS6600 ?

Quote from: Kleinstein
1) Noise, e.g. from the SMPS or just from the DAC: So maybe use just a DC or low amplitude sine.

DC out at 1V, AC coupled, output OFF:

(http://i.imgur.com/f9yb6nL.png)

Same as above, output ON:

(http://i.imgur.com/AqQyAbb.png)

Quote from: Kleinstein
2) DAC linearity: This can usually be seen from a slow triangle / ramp.

Triangle wave, 1KHz, 1Vpp:

(http://i.imgur.com/to3ksQ5.png)

Quote from: Kleinstein
3) Output amplifier slew rate: Many similar low cost generator run in to a slew rate limit with full amplitude and high frequency. So usually the maximum amplitude is reduces at the highers frequency.

Here's a sine wave, 25MHz, set to 1Vpp (but into a 50 Ohm load so what we 'should' see is 500mVpp)

(http://i.imgur.com/larC8Mw.png)

Same as above, but a square wave:

(http://i.imgur.com/fNuACLs.png)

Quote from: Kleinstein
4) There are 2 relays per output channel. So this could be an output attenuator. This has good sides, but might also limit the Offset range, when using low amplitudes.

Looks like you were right about the output attenuators, at 100mVpp setting (into 50 Ohms again), the maximum offset I can set is 0.25V;

(http://i.imgur.com/R6A6wjA.png)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: vk2seb on June 27, 2017, 04:34:40 PM
Quote from: RD Tech
what you test ? JDS6600 ?
Yes, all the waveforms I have posted are from the JDS6600.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 27, 2017, 04:45:15 PM
I received my JDS6600/25Mhz about a week ago and I am suitably impressed with its functionality. I have put it through some tests on a Siglent SDS 2204X 200Mhz DSO and it performs rather well. The two exceptions are a)  the power pack leaks 78 V AC measured from mains earth to the DC ground of the power pack. Leakage current is 14µA. Not life threatening and can be fixed by replacing it with a transformer based PS. b) Both BNC connector cables have a very intermittent and tenuous connection when plugged into the generator. Sometimes I cannot get a solid signal without putting side tension on the leads.
To vk2seb, I enjoyed your presentation video and noted the relay click noise was masked by the incessant transducer beep. There is a way to turn of the beep and save that setting so it never sounds unless you turn it on again. Also QBY's question regarding both channels syncing. As far as can see the SYS button lets you set the frequency, waveform, amplitude, offset and duty to track (sync) chan 1 and chan 2. This is also true in the software which drives the JDS6600 through the USB port. Altogether a nice piece of kit.
For the leak, I did not find it and the 5V power supply is definately safe, it is through Conformite Europende.
for the cable, please check the connection, there should be bad contact. you can check
if possible, please make a video to show all problem , or you can contact me by e-mail [email protected] ...
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 27, 2017, 04:48:06 PM
Quote from: gby
  4.  For changing the frequency when both channels are running the same frequency you say:
    "I couldn't find a way to change the frequency of both channels at once, so I'm not sure if that's possible"
These generators usually have a channel synchronization mode where you lock them such than changing one channel parameter changes both channels.  In the JDS66000 manual I found on line it says under the system setting menu:

4.4.2 Sync: When sync, CH1 is the object of operation. CH2 parameter will be changed with the changes of CH1 parameter. When the sync item is selected, you can press  or knob to select the sync item needed, press ON softkey to select and press OFF softkey to cancel.

Could you check for the system setting sync function and try changing the frequency of two channels locked at 90 Deg phase again?

You're dead right, a case of 'RTFM, vk2seb' ;).

Here's what that looks like 10KHz->20KHz, 90 deg phase lock, 5Vpp:

(http://i.imgur.com/nFfsSME.png)

So yeah, channel 2 is definitely not behaving there.

Quote from: gby
  5.  Perhaps with the two channels sync'ed you can then sweep two channels with a phase difference simultaneously??  One can only hope....

Good news: You can indeed sweep the 2 channels simultaneously.
Bad news: They don't stay in phase lock.

With a 0 deg phase set (sweeping 10KHz->20KHz):
(http://i.imgur.com/zNuMfLQ.png)

With a 90 deg phase set (sweeping 10KHz->20KHz):
(http://i.imgur.com/0VNpzz4.png)

Difficult to get a capture of the whole sweep without nothing meaningful being visible.

Quote from: gby
Again, thanks for your help in evaluating this generator and sharing.

No worries at all!
I just check all picture carefully, there is no problem, if you think there is some problem, please point it out, I will explain
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on June 27, 2017, 04:52:25 PM
Quote from: RD Tech
what you test ? JDS6600 ?
Yes, all the waveforms I have posted are from the JDS6600.
I just check all picture carefully, there is no problem, if you think there is some problem, please point it out, I will explain
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: gby on June 28, 2017, 10:59:03 AM
Quote from: RD Tech
what you test ? JDS6600 ?
Yes, all the waveforms I have posted are from the JDS6600.
I just check all picture carefully, there is no problem, if you think there is some problem, please point it out, I will explain

RD Tech,

You say you checked the pictures and "there is no problem".  The pictures may show the generator working as designed, but the pictures shown by vk2seb are NOT operating as needed by the users of a 2 phase generator.

First, let's talk about test number 4 where the two channels have sync for frequency turned on.  When the frequency set point is changed from 10 to 20 kHz what is needed is that both channels change frequency simultaneously and in a step manner with no glitches in either waveform.  In vk2seb's picture:

    - Yellow waveform (Ch 1) changes frequency in a step like manner with no glitches in phase or output voltage as desired
    - Blue waveform step changes phase (and not frequency) at the same instant in time that yellow changes frequency
    - about 20 uSec later the blue waveform steps to the new desired frequency and steps its phase
    - about 10 uSec later the blue waveform steps its phase again to be the proper phase relative to the yellow waveform

All the steps in the blue waveform are highly undesirable at the least and more typically mean the generator can NOT be used as a test source.  I highly suspect that the DSP FW steps the frequency on Ch 1 and then goes through a process spread out over about 30 uSec to change Ch 2 frequency and reset the relative phase to the phase set point.  The need is for both channels to step change in frequency at the same time like the Yellow waveform shows and have no voltage glitches.

Now lets talk about test number 5.  In this test the desire is to frequency sweep both output channels at the same time.  Furthermore the goal is to have the channels remain at the same frequency and at the same relative phase over the entire sweep with smooth changes (no glitches like shown in test 4).  The generator outputs have no glitches and are cleanly sweeping at the same time.  However, if you look at the waveforms it clearly shows the channels do not have a fixed relative phase between Ch 1 and Ch 2 over the sweep.

If my explanation above does not make sense I could publish working waveforms showing the correct behavior.  I can also give common usage examples where the measured behavior would mean the generator could not be used.   Lastly, if you want we could start a PM exchange to discuss what might be done to fix these waveforms and make this good generator even better.

gby
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: CharlieWorton on July 01, 2017, 10:27:08 AM
Yes!  Finally!  My JDS6600 has arrived!

Canada Post lost it for a couple of days, but after screaming at them loud enough to peel paint from a barn, I was able to convince them to bestir themselves, and lift a finger... and they discovered that they HAD mis-delivered it, and were able to retrieve it and get it into my hands.  :phew:

Of course, this would be the weekend that my sister is moving, so my weekend is shot - and I'm tearing apart my hobby room in preparation for painting it, so that will add a few days onto the far end.  So I won't have any decent time to play with my new toy for a while.  Sigh.

Hey, RD Tech!.  A little while ago, I posted
Quote
I don't believe the 60Mhz claim.  I'm sure there's something there, but I'll bet it winds up looking like a weak, wobbly triangle wave than a pure sine.

Yah, I must have been in a particularly bad mood when I typed that.  It does look a little harsh, just standing there on its own, and I regret having typed that.  So many products these days overstate their capabilities, especially the feeltech products.  I should not have spoken harshly of your product before I even saw it.  That was wrong of me, and I do apologize.

Speaking of the feeltech product, I came across a YouTube video in which a young engineer took it upon himself to improve on the old feeltech signal generator.  With the addition of a few jumper wires and a couple of components, he improved it a great deal.  The funny part was when he said," I don't know why they used XXXX part.  This other part is a much better match for what they're doing, and it's cheaper!"

Have a good one, everybody -  and Happy 150th Birthday, Canada!  Yea!!!!!! :clap: :clap: :clap:

Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 05, 2017, 08:50:59 PM
I also bought a signal generator, JDS6600 5mVPP effect is very poor, there is a clear switching power supply noise, more than 20MHz sine wave has a significant jitter, the nominal vertical resolution of 14, in fact, simply can not reach, Because the waveform length is only 2048 points, the highest resolution is only 11-bit resolution, the oscilloscope with 20mV voltage and 100nS time base gear test 5V 10Khz sine wave, you can see the rough rough waveform, and 14bit machine More than a lot of open the machine can see the DA is a simple resistor, which used a multiplier, or second-hand components, with a knife gently scraping the surface to drop the black powder.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: gby on July 06, 2017, 10:49:11 PM
Yes!  Finally!  My JDS6600 has arrived!
.
.
Speaking of the feeltech product, I came across a YouTube video in which a young engineer took it upon himself to improve on the old feeltech signal generator.  With the addition of a few jumper wires and a couple of components, he improved it a great deal.  The funny part was when he said," I don't know why they used XXXX part.  This other part is a much better match for what they're doing, and it's cheaper!"
.
.

Charlie,

I am familiar with a YouTube video to improve the MHS-5200 generator which had some serious output filter and output buffer issues.  See:

https://www.youtube.com/watch?v=-xOKNi8M3xE (https://www.youtube.com/watch?v=-xOKNi8M3xE)
http://www.analogzoo.com/2015/08/fixing-the-mhs-5200a/ (http://www.analogzoo.com/2015/08/fixing-the-mhs-5200a/)

However, I am not familiar with any such update for the Feeltech FY3200S generators.  Can you provide a link for a Feeltech improvement video or did you confuse the MHS-5200 one as a Feeltech update?

gby
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: bianchifan on July 11, 2017, 09:24:35 PM
Short review from a russian forum..

DDS generator JDS6600 (https://translate.google.com/translate?depth=1&hl=en&rurl=translate.google.com&sl=auto&tl=en&u=http://microsin.net/adminstuff/hardware/jds6600-dds-signal-generator-user-nanual.html) (Google translate)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 13, 2017, 10:32:26 PM
The device has a very poor Electromagnetic compatibility,
Interference is caused by DC / DC motherboard converters.
This is noticeable immediately after switching on, if we put a probe next to it.
Sensitivity 500uV / div
Bandwidth 300MHz
The probes of the oscilloscope are connected to ground, there is no signal at the input,  noise JDS6600  is very high.
https://youtu.be/T-0A7Yr3y3I

Seller photo Power off/on.


Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pascal_sweden on July 15, 2017, 05:37:42 AM
The device has a very poor Electromagnetic compatibility,
Interference is caused by DC / DC motherboard converters.
This is noticeable immediately after switching on, if we put a probe next to it.
Sensitivity 500uV / div
Bandwidth 300MHz
The probes of the oscilloscope are connected to ground, there is no signal at the input,  noise JDS6600  is very high.

Maybe it's because of your lousy way of connecting the probes to the signal generator.

Why on Earth don't you have decent BNC cables?

First time that I see a Rigol DS2000A user (supposed to be professional player) without decent cables :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 15, 2017, 06:07:23 AM
Maybe it's because of your lousy way of connecting the probes to the signal generator.
Of course yes.
If you turn on the bandwidth of 20MHz, interference will become significantly less.
But connected in the same way to the MHS5200A, with a full bandwidth there is no interference from the DC / DC converters of the motherboard.
The JDS6600 has a noise of the ground, With a repetition rate of 400kHz and a spectrum wider than 100MHz. I consider this a design error. The video was shot specially to show it.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 15, 2017, 06:11:40 AM
First time that I see a Rigol DS2000A user (supposed to be professional player) without decent cables :)
I'm not a professional, just an amateur. :)
Two signals, small approximately equal level.
Yes, the ground clamp loop catches radio interference, which creates a power source.
Now I need to think about how to reduce EMI, when the developer should take care of it.
JDS6600
Analog no name.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pascal_sweden on July 15, 2017, 08:40:06 AM
If I am correct, the actual designer of this signal generator is in this thread. Maybe you can PM him with your suggestions to further improve the design.

I will wait ordering the device until the Mark II version becomes available :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 15, 2017, 02:06:51 PM
If I am correct, the actual designer of this signal generator is in this thread. Maybe you can PM him with your suggestions to further improve the design.
Probably the designer needs to study AN139 - Power Supply Layout and EMI
http://cds.linear.com/docs/en/application-note/an139f.pdf (http://cds.linear.com/docs/en/application-note/an139f.pdf)
Why should I pay for other people's mistakes, and then help solve the problem?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pascal_sweden on July 15, 2017, 05:32:37 PM
Maybe he will thank you with a free trade-in for a Mark II model :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Phildem on July 18, 2017, 05:07:12 PM
I juste tested a JDS6600 60MHz model and it has a big problem, when set on certain frequency there is a phase shit
Here is the way to get it
-Set default setting
-Set 50Khz 5vpp Sine

The Shift occur, making the scope sync impossible

It is audible on certain freg, near 1Khz, it produce tics
(https://scontent-cdg2-1.xx.fbcdn.net/v/t1.0-9/20046367_10155391768639693_850153226978238696_n.jpg?oh=8c3b0b3623924fb807a5a76673842771&oe=59C6A24F)

For me this issus make it unsusable..
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 19, 2017, 01:40:09 PM
I juste tested a JDS6600 60MHz model and it has a big problem, when set on certain frequency there is a phase shit
8MHz, I did not notice this
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Phildem on July 19, 2017, 07:11:07 PM
Hi,

I've been in touch with the manufacturer, I've got a defective unit by mistake.
This default has been fixed  :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 20, 2017, 01:33:31 PM
JDS6600 Phase does not sync
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 20, 2017, 02:09:09 PM
Sine wave is not 14bit, waveform data only 2048 points, the resolution is only 11bit, the waveform is very rough
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 20, 2017, 02:14:51 PM
JDS6600 Phase does not sync
Yes :horse:
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Messtechniker on July 20, 2017, 06:07:08 PM
Does the JDS6600 carry a CE mark?

I'm asking, because without it German customs may
have me return the unit or scrap it at my cost which is not funny.

Yes, I know the CE story. It basically means China Export :-DD
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on July 21, 2017, 01:08:15 AM
Having 11 Bit resolution is already quite good from an simple R2R chain at the FPGA. For me it looks surprisingly good.
Medium grade DDS chips like the AD9850 only use an 10 Bit ADC, though they use a longer table (e.g. 4096 points). With just 2048 points for a period, there is limited use of more than 10 Bit resolution though.

The staircase like waveform with quite some ringing suggests that there is no good reconstruction filter. So one can expect quite some high frequency images. The fast output amplifier also has some disadvantages here.

Some jitter in the square wave is normal for directly generating the square from the FPGA.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 21, 2017, 10:40:49 AM
R2R resistor network to achieve 11bit resolution is indeed very good, I do not know if you have not observed 14bit signal generator, the waveform is much better than this good, the use of R2R resistor network there is a drawback, that is, noise Problem, do not know if you have not found a small signal noise is very large, because the digital signal is grounded and the analog signal ground will not be separated, so the noise in the digital signal will interfere with the analog signal. I bought the JD6600 signal generator when the seller introduced a resolution of 14bit, but the actual waveform is only 11bit, I think I was cheated, and this business with the integrity and honesty have a great relationship. |O |O |O |O
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on July 21, 2017, 05:47:02 PM
Form the picture it looks like the DAC is not a pure R2R chain, but more like using thermometer style for the upper bits. So maybe someone confuses the 14 I/O pins used for control with a 14 bit resolution. At least the DAC seems to work reasonably well as 11 Bit this way.

The DAC type does not have direct influence on the noise with small signals. The waveform should be generated at constant amplitude and only the following multiplier and attenuators reduce the amplitude if needed.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 21, 2017, 06:05:08 PM
R2R resistor network to do out of the signal generator and DAC out of the signal generator to produce the waveform is completely different, if the same, the production of DAC manufacturers do not need to exist,
Directly with a few resistance can produce a DAC, digital signals and analog signals if not isolated, the noise can not be eliminated, there is, FPGA I / O port drive capacity is limited, not every I / O The current generated by the mouth will be exactly the same, which is the reason for the instability of the waveform, 11bit and 14bit waveform generated by a great difference, I do not know if you have not carefully observed, 14 I / O port can not say that the resolution of 14bit , He also has a large number of data stored with the waveform has a great relationship.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 21, 2017, 06:16:07 PM
Form the picture it looks like the DAC is not a pure R2R chain, but more like using thermometer style for the upper bits. So maybe someone confuses the 14 I/O pins used for control with a 14 bit resolution. At least the DAC seems to work reasonably well as 11 Bit this way.

The DAC type does not have direct influence on the noise with small signals. The waveform should be generated at constant amplitude and only the following multiplier and attenuators reduce the amplitude if needed.

You can look at the delicate degree of 14bit waveform
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on July 21, 2017, 06:59:05 PM
A special DAC chip is generally better than using just a resistor chain at the FPGA output. Most DACs do not offer that much of isolation between the digital side and analog output. So noise is in both cases a question of a good layout. This is still a low cost generator - so the cheap resistor ladder DAC is a kind of compromise.

The failure is to label it 14 Bit resolution if they actually only get 11 Bits.

The Resistor chain looks like 8 Bit R2R and 14 or 15 resistors thermometer style. So at best they could get something like 12 Bit resolution. Still I am surprised how good it seemed to work. If not careful, even at 8 Bits R2R one can get significant errors. One sees that with other low cost generators that call for 8 or 12 Bit resolution and only deliver 6-7.  With an actual 11 Bit resolution it is already a big step forward.

Using true 14 or maybe just 12 Bit DACs is a cost factor - though they might save on the amplitude control this way.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 21, 2017, 11:57:35 PM
You can look at the delicate degree of 14bit waveform
Do you have a FY6600?
It can amplitude and frequency modulation and has a sync output?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 22, 2017, 12:17:59 PM
You can look at the delicate degree of 14bit waveform
Do you have a FY6600?
It can amplitude and frequency modulation and has a sync output?

I have one, the parameters look better than the JDS6600 much better, I found a user manual and parameter description, you can look at
https://drive.google.com/file/d/0B3N_NW8vylrmWFZQWkRnWDI5cms/view?usp=sharing
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 22, 2017, 10:21:32 PM
I have one
When the frequency is tuned, the phase of the synchronized 2 channel does not change for a short time?
This is important if at 1 and 2 output an antiphase pulse signal with a deadtime, used to control the inverter.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 22, 2017, 10:36:23 PM
I have one
When the frequency is tuned, the phase of the synchronized 2 channel does not change for a short time?
This is important if at 1 and 2 output an antiphase pulse signal with a deadtime, used to control the inverter.

The phase of the adjustment frequency CH2 changes because it needs to synchronize the CH1 signal, but the adjustment amplitude and the bias level do not change
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 22, 2017, 10:49:19 PM
The phase of the adjustment frequency CH2 changes because it needs to synchronize the CH1 signal
MHS5200A phase does not change, at least the deadtime does not intersect.
The only generator that made me for this reason.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 22, 2017, 11:28:09 PM
The phase of the adjustment frequency CH2 changes because it needs to synchronize the CH1 signal
MHS5200A phase does not change, at least the deadtime does not intersect.
The only generator that made me for this reason.
I have just tested my instrument to adjust the frequency of the CH1 channel when the CH2 phase does not change, maybe I have an error in his understanding
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: gby on July 22, 2017, 11:42:56 PM
The Feeltech FY6600 has so many differences to the JDS6600:
   "Real" 14 bit DAC vs. discrete resistor driven by FPGA pins
    8192 point arbitrary table at 250 Mhz vs. 2048 points at 200 MHz
    Analog input for modulation source of frequency, amplitude, duty cycle vs. none (unfortunately limited to 1000 Hz)
    Digital modulation mode: ASK, FSK, PSK from external input vs. none

With these differences and more I suggest that the Feeltech FY6600 generator deserves its own thread for discussion.  It would be great to see some pictures of the insides and see some performance testing like I asked Vk2seb to do on the JDS6600.  See https://www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator/msg1240865/#msg1240865 (https://www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator/msg1240865/#msg1240865)

Hopefully an early FY6600 owner can get this started.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 23, 2017, 12:30:02 AM
I have just tested my instrument to adjust the frequency of the CH1 channel when the CH2 phase does not change, maybe I have an error in his understanding
A successful and unsuccessful frequency tuning, the pulses of channels 1 and 2 should not overlap.

Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Diabolo on July 23, 2017, 10:00:57 AM
Hello,

At the request of @gby

Here is the new Feeltech DDS generator 14 bits-250 msa-8192 points without R2R equipped with an Altera Cyclone IV clocked with SPXO 50mhz .
The model I bought is FY2300H-25 Mhz.
(http://img15.hostingpics.net/thumbs/mini_305215FY2300H25mhz.jpg) (http://www.hostingpics.net/viewer.php?id=305215FY2300H25mhz.jpg)

regards,
Diabolo
https://www.eevblog.com/forum/testgear/new-generateur-dds-avec-altera-cyclone4/ (https://www.eevblog.com/forum/testgear/new-generateur-dds-avec-altera-cyclone4/)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: colorado.rob on July 23, 2017, 11:54:20 AM
Here is the new Feeltech DDS generator 14 bits-250 msa-8192 points without R2R equipped with an Altera Cyclone IV clocked with SPXO 50mhz .
The model I bought is FY2300H-25 Mhz.
(http://img15.hostingpics.net/thumbs/mini_305215FY2300H25mhz.jpg) (http://www.hostingpics.net/viewer.php?id=305215FY2300H25mhz.jpg)
What are the missing ICs for?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Diabolo on July 23, 2017, 01:20:19 PM
Hello,

For the absent CIs I do not know.
They may be for a more powerful version, or with little interest for this version.
The generator works very well and the signals are good.
Without advertising, I am very satisfied with this device.

Regards,
Diabolo
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 24, 2017, 12:04:05 PM
Hello,

At the request of @gby

Here is the new Feeltech DDS generator 14 bits-250 msa-8192 points without R2R equipped with an Altera Cyclone IV clocked with SPXO 50mhz .
The model I bought is FY2300H-25 Mhz.
(http://img15.hostingpics.net/thumbs/mini_305215FY2300H25mhz.jpg) (http://www.hostingpics.net/viewer.php?id=305215FY2300H25mhz.jpg)

regards,
Diabolo
https://www.eevblog.com/forum/testgear/new-generateur-dds-avec-altera-cyclone4/ (https://www.eevblog.com/forum/testgear/new-generateur-dds-avec-altera-cyclone4/)



Well-known brands of signal generators are all using DAC, which is R2R resistor network can not go beyond
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: technogeeky on July 24, 2017, 03:23:45 PM
Form the picture it looks like the DAC is not a pure R2R chain, but more like using thermometer style for the upper bits. So maybe someone confuses the 14 I/O pins used for control with a 14 bit resolution. At least the DAC seems to work reasonably well as 11 Bit this way.

The DAC type does not have direct influence on the noise with small signals. The waveform should be generated at constant amplitude and only the following multiplier and attenuators reduce the amplitude if needed.

You can look at the delicate degree of 14bit waveform

I'm sorry to be rude, but I am a bit concerned about your posts in this thread. I think you are trying to imply from the context and content of your posts that you are a mere consumer who has tried the Rui-Deng model and a FeelTech model function generator. Your profile says you're from England.

However:

I should note that all of this is just from information you offered (your username, listing feeltech in your profile) or otherwise publicly available information. And I don't know of any reason or rule that one's profile must be correct on this forum, so I doubt you've done anything wrong. I suppose I could believe that you are an Chinese expat living in the UK.

In any case, if you do work for Feeltech (and perhaps if you designed the product you are discussing) I  think you should be up front and honest about that fact. After all, who else would be better qualified to analyze the properties of a modern cheap function generator than a person who just designed a modern cheap function generator?

Thanks.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 24, 2017, 04:37:54 PM
The JDS6600 on the main signals does not have one clock jitter, if the duty cycle is 50%, but it is 5ns if the duty cycle is not 50%
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Kleinstein on July 24, 2017, 06:53:29 PM
The jitter should not depend on the H/L ratio. It should be just a question of the 5 ns time raster. So it depends on the frequency too. This might even be the worst aspect of it. At frequencies that don't have a period that is an integer multiple of 5 ns will show the jitter. So more like low jitter only at a few special good frequencies.

Depending on how frequency calibration is done the good frequencies can be slightly different, depending on the exact quartz frequency. In principle they could use a different frequency scale - allowing only good ones (e.g. divider) and maybe warn about poor ones.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 24, 2017, 07:31:44 PM
JDS6600 Phase does not sync
Yes :horse:
I have admite and explain , we have improve this , this don't affect normall using ...
about this little problem, we are updating this.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 24, 2017, 07:36:38 PM
Does the JDS6600 carry a CE mark?

I'm asking, because without it German customs may
have me return the unit or scrap it at my cost which is not funny.

Yes, I know the CE story. It basically means China Export :-DD
yes, we have CE mark for JDS6600, you can go to our page to check
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 24, 2017, 08:07:49 PM
Having 11 Bit resolution is already quite good from an simple R2R chain at the FPGA. For me it looks surprisingly good.
Medium grade DDS chips like the AD9850 only use an 10 Bit ADC, though they use a longer table (e.g. 4096 points). With just 2048 points for a period, there is limited use of more than 10 Bit resolution though.

The staircase like waveform with quite some ringing suggests that there is no good reconstruction filter. So one can expect quite some high frequency images. The fast output amplifier also has some disadvantages here.

Some jitter in the square wave is normal for directly generating the square from the FPGA.
thank you for your answer, our Waveform vertical resolution is 12 bit, 4096 points, and waveform is about 2048 points . so at x-2048 points, y-4096 points, at this
coordinate system, it show our waveform. For  R2R , it is not easy to design, because it is hard to design, so many DDS don't use this way, if it is design better , it will be more stable than chiop way.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 24, 2017, 08:19:31 PM
The jitter should not depend on the H/L ratio. It should be just a question of the 5 ns time raster. So it depends on the frequency too. This might even be the worst aspect of it. At frequencies that don't have a period that is an integer multiple of 5 ns will show the jitter. So more like low jitter only at a few special good frequencies.
This generator does not have jitter at non-multiple frequencies, unlike other budget DDS.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Diabolo on July 25, 2017, 03:41:08 AM
Hello,

Here are some curves with FY2300H.
Square 10Mhz
- (http://img15.hostingpics.net/thumbs/mini_350730Square10Mhz.png) (http://www.hostingpics.net/viewer.php?id=350730Square10Mhz.png)
Sinus 25 Mhz
- (http://img15.hostingpics.net/thumbs/mini_791073Sinus25Mhz.png) (http://www.hostingpics.net/viewer.php?id=791073Sinus25Mhz.png)
Triangle 20 Mhz
- (https://img15.hostingpics.net/thumbs/mini_390575Triangle20mhz.png) (https://www.hostingpics.net/viewer.php?id=390575Triangle20mhz.png)

Only everything is not perfect, the suite is here:
- https://www.eevblog.com/forum/testgear/new-generateur-dds-avec-altera-cyclone4/ (https://www.eevblog.com/forum/testgear/new-generateur-dds-avec-altera-cyclone4/)

Sorry for the hs.
Regards,
Diabolo
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: Enoch on July 25, 2017, 12:48:23 PM
I received my JDS6600 yesterday, phase tracking no problem. :scared:
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 25, 2017, 03:54:29 PM
I received my JDS6600 yesterday, phase tracking no problem. :scared:
Turn on infinite persistence And tuning of frequencies.
When the frequency is tuned, the synchronized second channel loses the phase randomly.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 25, 2017, 04:06:04 PM
The jitter should not depend on the H/L ratio. It should be just a question of the 5 ns time raster. So it depends on the frequency too. This might even be the worst aspect of it. At frequencies that don't have a period that is an integer multiple of 5 ns will show the jitter. So more like low jitter only at a few special good frequencies.
This generator does not have jitter at non-multiple frequencies, unlike other budget DDS.
at square wave, our wave is not jitter . this is my advantage. so you have JDS6600, you can check
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 25, 2017, 04:10:24 PM
The jitter should not depend on the H/L ratio. It should be just a question of the 5 ns time raster. So it depends on the frequency too. This might even be the worst aspect of it. At frequencies that don't have a period that is an integer multiple of 5 ns will show the jitter. So more like low jitter only at a few special good frequencies.

Depending on how frequency calibration is done the good frequencies can be slightly different, depending on the exact quartz frequency. In principle they could use a different frequency scale - allowing only good ones (e.g. divider) and maybe warn about poor ones.
yes, that is a standar too to judage a DDS
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 25, 2017, 04:19:21 PM
A special DAC chip is generally better than using just a resistor chain at the FPGA output. Most DACs do not offer that much of isolation between the digital side and analog output. So noise is in both cases a question of a good layout. This is still a low cost generator - so the cheap resistor ladder DAC is a kind of compromise.

The failure is to label it 14 Bit resolution if they actually only get 11 Bits.

The Resistor chain looks like 8 Bit R2R and 14 or 15 resistors thermometer style. So at best they could get something like 12 Bit resolution. Still I am surprised how good it seemed to work. If not careful, even at 8 Bits R2R one can get significant errors. One sees that with other low cost generators that call for 8 or 12 Bit resolution and only deliver 6-7.  With an actual 11 Bit resolution it is already a big step forward.

Using true 14 or maybe just 12 Bit DACs is a cost factor - though they might save on the amplitude control this way.
About  a resistor chain at the FPGA output, I have explain, and your explain is good and right too , for any plan, it was designed better , it will all be good.
about the bit, I don't why where you find, because we write 12 bit Waveform vertical resolution , not 14bit.
about the 14 bit , we have updated, but we only sell at china for now. because we need to test in china, after test, and no one find the problem, so we sell to the world. it is our rule for publishing the products. all our products have this progress.
thank you for your support again
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pantelei4 on July 25, 2017, 04:23:42 PM
we have updated, but we only sell at china for now. because we need to test in china, after test, and no one find the problem, so we sell to the world. it is our rule for publishing the products. all our products have this progress.
thank you for your support again
Why then I received an imperfect product? |O
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: qq354813374 on July 25, 2017, 04:40:29 PM
Form the picture it looks like the DAC is not a pure R2R chain, but more like using thermometer style for the upper bits. So maybe someone confuses the 14 I/O pins used for control with a 14 bit resolution. At least the DAC seems to work reasonably well as 11 Bit this way.

The DAC type does not have direct influence on the noise with small signals. The waveform should be generated at constant amplitude and only the following multiplier and attenuators reduce the amplitude if needed.

You can look at the delicate degree of 14bit waveform

I'm sorry to be rude, but I am a bit concerned about your posts in this thread. I think you are trying to imply from the context and content of your posts that you are a mere consumer who has tried the Rui-Deng model and a FeelTech model function generator. Your profile says you're from England.

However:
  • you list "feeltech" in your profile
  • your username is typical of the email addresses offered primarily to Chinese users by Tencent
  • a google search for that username reveals other posts in Chinese in various technical forums
  • your English, while adequate, leads me to believe you speak English as a second language
  • FeelTech is headquartered in China, and I'm not able to find any offices in the UK

I should note that all of this is just from information you offered (your username, listing feeltech in your profile) or otherwise publicly available information. And I don't know of any reason or rule that one's profile must be correct on this forum, so I doubt you've done anything wrong. I suppose I could believe that you are an Chinese expat living in the UK.

In any case, if you do work for Feeltech (and perhaps if you designed the product you are discussing) I  think you should be up front and honest about that fact. After all, who else would be better qualified to analyze the properties of a modern cheap function generator than a person who just designed a modern cheap function generator?

Thanks.

First of all, I am a Chinese, I did not deliberately hide my nationality, I and everyone like FeelTech users, which is me in the "forum" learning reasons, because here you can get more technical articles, out of By chance, I saw RD Tech in the forum to promote FeelTech product designers are their students, so I will call to FeelTecH confirmation. Got FeelTecH designer Sun Yi Jie negative answer. At the request of Sun Yi Jie, I made a comparison of the FY6600 and JDSS6600, responded to the "Forum"


Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on July 26, 2017, 04:28:09 PM
products are being updated. we are working on it. if we sloved alll problem, i will tell you
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: SaabFAN on August 03, 2017, 06:44:14 AM
Can these problems be fixed in software and can user update the firmware themselves?

Or is this more a hardware-issue?
How can customers tell the difference between the updated and non-updated devices?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on August 03, 2017, 01:53:09 PM
Can these problems be fixed in software and can user update the firmware themselves?

Or is this more a hardware-issue?
How can customers tell the difference between the updated and non-updated devices?
there are two small problem,
1, background noise, it was caused by DC power supply. it is small and it doesn't affect normal using , I can make sure
2, at low frequency for square wave form, when you amplify 1000 times, you will find that there is little no sync. this don't affect normal using .
excep those , otheres are not my problem.
because those are small problem and don't affect normal using , so we gradually update those things. now we have already update 2 problem, if you order now
thank you for your concern
have a nice day
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: SaabFAN on August 04, 2017, 05:20:17 AM
Okay, good to know.
But is there a possibility to install new Firmware via USB, or can the Firmware only be updated by programming the microcontroller via the JTAG-Header?

If the latter is the case, I'd suggest that this feature is implemented as soon as possible, as it will add significant value to the instrument. If any problem is discovered that can be corrected with a firmware-update, users can just update to the new firmware instead of buying a new unit or living with that problem. It also allows you to add features later, maybe as paid options, further adding value.
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: SaabFAN on August 04, 2017, 05:31:37 AM
It also appears that the JDS6600 does not have the capability to modulate the signal, is that correct?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on August 04, 2017, 05:50:47 PM
Okay, good to know.
But is there a possibility to install new Firmware via USB, or can the Firmware only be updated by programming the microcontroller via the JTAG-Header?

If the latter is the case, I'd suggest that this feature is implemented as soon as possible, as it will add significant value to the instrument. If any problem is discovered that can be corrected with a firmware-update, users can just update to the new firmware instead of buying a new unit or living with that problem. It also allows you to add features later, maybe as paid options, further adding value.
Thank you for your reply , friend
in fact , those are no problem. it don't affect our using totally. we only say it is not perfect, because there is no perfect thing in the world. those thing are just like there is small dot on shell of a device , those don't affect normal using totally, useless you use a magnifying glass to see , you can see this dot.
but we are trying to make it perfect .. thank you
about the modulating the signal , we don't have this function, because this is a just DDS signal generator ..
thank you again . hope you understansd what I said
 :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on August 28, 2017, 04:16:44 PM
Brands shopping week will begin from 28st Aug to 1 st Sep ( US time). There is the Biggest discount in this year on aliexpress, there are many coupons on aliexpress. And our shop discount is from 17% off - 30% off. And there are many coupons:
8 usd for over 75 usd value at home page  (https://rdtech.aliexpress.com/store/923042 )
And 2 USD , 3 USD . 5 USD coupons.
1, DP and DPS power supply : 24%-30% off https://rdtech.aliexpress.com/store/group/Power-Supply-module/923042_252253169.html?spm=2114.12010608.0.0.2995e5c0hedOO2
2, USB Tester meter : 24%-30% off https://rdtech.aliexpress.com/store/group/USB-Tester-meter/923042_250764074.html?spm=2114.12010612.0.0.5bdadf47DMFSF9
3, 7 in 1 OLED multifunction meter 24%-27% off https://rdtech.aliexpress.com/store/group/7-in-1-OLED-METER/923042_502024032.html?spm=2114.12010612.0.0.5bdadf47VDGoeX
4, JDS6600 : 20% off (23% off at phone app) https://rdtech.aliexpress.com/store/group/DDS-SIGNAL-GENERATOR/923042_252907419.html?spm=2114.12010612.0.0.5bdadf47O3g0YO
Hope this can help you. Happy shopping
Have a nice day
Best Regards
RD official store
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: smarteebit on September 02, 2017, 05:58:16 PM
yes, we have CE mark for JDS6600, you can go to our page to check

Where is your web page?  Could you please provide your official website?
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on September 02, 2017, 06:46:16 PM
yes, we have CE mark for JDS6600, you can go to our page to check

Where is your web page?  Could you please provide your official website?
https://rdtech.aliexpress.com/store/923042
you can check
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: pascal_sweden on September 02, 2017, 07:20:55 PM
Do you maintain a list with an overview of all known hardware and software problems?

In this list you can each time add new problems and also indicate which problems that are solved.

You can give each problem a title, and classify it as a hardware problem, a software problem or a combination of both.

You can indicate in which hardware revision, and/or software revision the problem has been solved.

When customers order a product on your webstore, you can indicate which hardware revision and which software revision they will get. This avoids discussions later on, as the customer will know upfront what he will get.

Good luck in fixing all your hardware and software problems! :)
Title: Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
Post by: RD Tech on September 04, 2017, 01:05:39 PM
Do you maintain a list with an overview of all known hardware and software problems?

In this list you can each time add new problems and also indicate which problems that are solved.

You can give each problem a title, and classify it as a hardware problem, a software problem or a combination of both.

You can indicate in which hardware revision, and/or software revision the problem has been solved.

When customers order a product on your webstore, you can indicate which hardware revision and which software revision they will get. This avoids discussions later on, as the customer will know upfront what he will get.

Good luck in fixing all your hardware and software problems! :)
thank you so much for your advice , it is good idea.
but we did not make a record . because those problem is small problem, don't affect normally using , so we did not record those .
thank you again
now we have update all those small problem.