Juntek PSG9080 duty cycle problem?

[ptluis]

Hello, according to the user radiolistener, duty cycle doesn't work properly for the frequency 1'000'000 Hz and above. Does anyone have similar problems?

 
on this post https://www.eevblog.com/forum/testgear/juntek-psg9080-programmable-signal-generator-(80-mhz-300-msas-14-bit)/75/

Duty cycle don't works properly for the frequency 1'000'000 Hz and above. If you set 999'999 Hz or below that it works ok. But when you set frequency just 1 Hz above, the duty cycle setting is no more works as expected. This is obviously firmware bug, probably just some kind of mistyping in the source code or something like that. But be aware, with current FPGA firmware 1.20 you will be unable to setup duty cycle for the frequency 1 MHz and above. You can setup duty cycle for higher frequency on the display UI, but the actual signal output will be invalid. It stays close to 50% for any setting from 0 to 99.99%, but it is not exactly 50%, the actual duty cycle changes for about 2-5% instead of 0-100%.

[radiolistener]

Yes, my device has such issue. But it's hard to imagine the case when you will needs to change duty cycle for signals above 1 MHz. And below 1 MHz duty cycle works ok. Also you can use workaround with arbitrary waveform, just upload user waveform with desired duty cycle and use it

Is your device has the same issue? I think that bug should be fixed in a new devices with a more fresh firmware version.

[ptluis]

... it's hard to imagine the case when you will needs to change duty cycle for signals above 1 MHz. And below 1 MHz duty cycle works ok. Also you can use workaround with arbitrary waveform, just upload user waveform with desired duty cycle and use it

Is your device has the same issue? I think that bug should be fixed in a new devices with a more fresh firmware version.

I cancel my purchase. Can't use a device like that, because duty cycle is adjusted realtime several times manually in fast/slow rate, randomly, so a non working feature like this makes the device useless. This PG9080 will be ideal because it has a programming feature that could help me automate the procedure, but unfortunately duty cycle doesn't work properly.

BTW, why don't you try to contact the manufacturer directly and expose your problem?

try here:
https://www.alibaba.com/product-detail/JUNCTEK-best-selling-80MHz-PSG9080-arbitrary_1600157247201.html

[ledtester]

BTW, why don't you try to contact the manufacturer directly and expose your problem?

try here:
https://www.alibaba.com/product-detail/JUNCTEK-best-selling-80MHz-PSG9080-arbitrary_1600157247201.html

There appear to be a couple of different re-brandings of the same device, including:

- JUNTEK    -- https://www.aliexpress.com/item/4001272913040.html
- JUNCTEK  -- https://www.aliexpress.com/item/1005001951923499.html
- Goupchn   -- https://www.aliexpress.com/item/1005001890059322.html

I think Juntek is the original manufacturer.

[ptluis]

BTW, why don't you try to contact the manufacturer directly and expose your problem?

try here:
https://www.alibaba.com/product-detail/JUNCTEK-best-selling-80MHz-PSG9080-arbitrary_1600157247201.html

There appear to be a couple of different re-brandings of the same device, including:

- JUNTEK    -- https://www.aliexpress.com/item/4001272913040.html
- JUNCTEK  -- https://www.aliexpress.com/item/1005001951923499.html
- Goupchn   -- https://www.aliexpress.com/item/1005001890059322.html

I think Juntek is the original manufacturer.

Hangzhou Junce Instruments Co., Ltd
I contacted them.
they can customize the equipment as requested, on a minimum order. Because of this customization, firmware from different brands are incompatible.
Why they change name from juntek to junctek I don't know, forgot to ask, but they won't answer to my technical questions because I don't own the device/serial number and can't send video proof to them.

you have here 2 emails you can use to contact them.
https://juntek.en.alibaba.com/?spm=a2700.details.cordpanyb.2.22203f6brJhK8u
Go through alibaba platform, it's much better.
and remember chinese work for profit 

[ledtester]

...
Why they change name from juntek to junctek I don't know,
...

Honestly, when I see "Junctek" I think of pronouncing it "junk tech" because in the English word "junction" the "c" is hard. Maybe they intended for it to be a soft "c" like in the word "juice" but that's not what comes to mind.

[radiolistener]

BTW, why don't you try to contact the manufacturer directly and expose your problem?

I tried, but they just don't answer.
When I ask simple question, they answer, but it take about two weeks for response.
But when I ask about bugs, they just no respond at all... I sent email in December 2020, but still no answer.

Their site is broken now, so I'm not sure what happens, maybe they sold company and now it is produced by another manufacturer. I have no idea.

There appear to be a couple of different re-brandings of the same device, including:

- JUNTEK    -- https://www.aliexpress.com/item/4001272913040.html
- JUNCTEK  -- https://www.aliexpress.com/item/1005001951923499.html
- Goupchn   -- https://www.aliexpress.com/item/1005001890059322.html

I think Juntek is the original manufacturer.

Here is also Joy-IT: https://joy-it.net/en/products/JT-PSG9080

I asked them if their firmware is compatible with Juntek brand, they wrote that it isn't.
So you cannot use firmware from different brand.

[ptluis]

Honestly, when I see "Junctek" I think of pronouncing it "junk tech" because in the English word "junction" the "c" is hard. Maybe they intended for it to be a soft "c" like in the word "juice" but that's not what comes to mind.

anyway I don't consider these low cost devices junk, but affordable devices to fulfill certain needs without having to spend hundreds of euros and be afraid of damaging them in certain tasks.  of course for demanding engineers, or perfectionists it not suitable. I've been using intensively the feeltech fy6800 not for RF, but for other things and has been efficient, and i'm not afraid if it get damaged because it's cheap and I can replace it easily. If I were to build one from scratch I will spend a lot more and it will be much more time consuming, time that I don't have. But of course I would like to own a siglent SDG2082X (€724.47 actual price) but I have other priorities in my life that consumes all my money and time. so cheap chinese junCtek are enough 

[radiolistener]

ptluis

PSG9080 is just a little better than FY6800, they are from the same class. The main advantage of PSG9080 is a larger display and better buttons on front panel. It's front panel is really nice. On alibaba it cost about 100-120 USD, a little higher than FY6800, but the price is comparable.

I think these prices 200-300 EUR is just marketing and it will be reduced after some time. But on the other hand who knows, with these logistic issues it is possible that we can see 200-300 EUR for FY6800 soon

[ptluis]

ptluis

PSG9080 is just a little better than FY6800, they are from the same class. The main advantage of PSG9080 is a larger display and better buttons on front panel. It's front panel is really nice. On alibaba it cost about 100-120 USD, a little higher than FY6800, but the price is comparable.

I think these prices 200-300 EUR is just marketing and it will be reduced after some time. But on the other hand who knows, with these logistic issues it is possible that we can see 200-300 EUR for FY6800 soon

fy6800 around 200-300€ I sell mine 
Psg9080 is better than fy6800 I agree with that, but prices are around 110€, I still keep my purchase on standby, if I get a good deal I'll  buy one.

Today my fy6800 suffered a little, I hacked my UNI-T UTG932 to 60MHz and to test it, I remove the cxo from my fy6800 and injected the clock using the Unit, works perfect! tested from 3MHz up to 60MHz. At 60MHz cxo, the fy6800 outputs a stable 72MHz sinewave.

Then I remember my old days when I overclocked Intel CPU's up to the extreme and decided to search my old parts box and found an old CXO of 100MHz...

He can do it?  well, after connect it to fy6800, I set the output to 60MHz press the ch1 and BAMM! the damm machine outputs a stable 120MHz sinewave at 5Vpp     
This fy6800 even boot without cxo, must be the devil It's a true war machine!