JunTek PSG9080 Programmable Signal Generator (80 MHz - 300 MSa/s - 14-bit)

[pascal_sweden]

Anybody on this forum here who has experience with the JunTek PSG9080 Programmable Signal Generator?



Official website:
http://junteks.com/product/278017415

Pricing on AliExpress:
https://www.aliexpress.com/item/4001271854079.html?spm=2114.12010612.8148356.1.35d43705FtlC8A

[pascal_sweden]

Anybody with this signal generator?

[JOHN LEE]

I have already purchased one and will share it with you after receiving it

[pascal_sweden]

Excellent!

I look forward to your two upcoming videos on YouTube

1) Unboxing video

2) Product review video

[TheDefpom]

Juntek contacted me today asking if I was interested in taking a look at a unit, so if all goes well I will be getting one to do a review video on in the near future, so if you are not already subscribed to my YouTube channel I suggest you go there now and Sub to get to see the video when it is done (assuming all goes ahead).

https://www.youtube.com/TheDefpom

[pascal_sweden]

I contacted them before to ask them for a new unit so that I can do a review.

[electronx]

The price looks very good. Frankly, I wonder if I can send the mathematical functions through the communication port with the quick control interface matlab. Let's try it.

[JOHN LEE]

If you want to test PSG9080, you can contact their promotion person at "lk0629@foxmail.com". After the review is passed, he will send you a new product test. I hope my message will be helpful to you.

[SERJSOCHI]

Does this generator have a sweep sync output signal (see picture)?

[radiolistener]

Just got this unit. Front panel is beautiful and convenient in use.
Some buttons have glowing back-light, it looks very cool in the dark
Device case has a convenient stand and looks very good.

Output amplitude up to 25 Vpp (12.5 Vpk) below 1 MHz.


Minimum amplitude 1 mVpp (0.5 mVpk).


DC offset can be set from -10V to +14V with 0.01 V resolution.

Here is 11 MHz 6 Vpp with 50 Ohm oscilloscope input:


It has modulation mode from internal or external source.


Also it has a frequency meter and pulse counter mode for external source.According to my tests, the minimum sense voltage for external input is:
- 0.65 Vpk with AC coupling;
- 2.4 Vpk with DC coupling.

Let me know what you want to test

[TheDefpom]

I just finished recording the review and teardown for this (literally two minutes ago!)

The unit is pretty nice, it does have some output voltage linearity issues (it decreases as the frequency increases), but it doesn't really drop that much, you will be able to see that in the video when I publish it, as I show it and step through the frequencies to find out where its dips and peaks are.

I also really like the frequency fine tune in the menu which lets you adjust its output frequency to be more accurate, from factory it is at 50% adjustment, I adjusted mine to 58% to get it almost bang on frequency, unfortunately though this adjustment doesn't have an effect on the frequency counter input, that seems to be a seperate reference (or is not software tied to the fine tuning).

I will publish the video next week once I have had time to edit it etc.

[radiolistener]

I also really like the frequency fine tune in the menu which lets you adjust its output frequency to be more m from factory it is at 50% adjustment, I adjusted mine to 58% to get it almost bang on frequency, unfortunately though this adjustment doesn't have an effect on the frequency counter input, that seems to be a seperate reference (or is not software tied to the fine tuning).

yes, I also notice that frequency fine tune doesn't affect frequency meter.

Here is actual frequency output on my unit for 50 MHz setting and different frequency fine tuning value:
- 49.999713 MHz for setting 49
- 49.999765 MHz for setting 50 (default)
- 49.999817 MHz for setting 51
- 49.999869 MHz for setting 52
- 49.999921 MHz for setting 53
- 49.999973 MHz for setting 54
- 50.000026 MHz for setting 55
- 50.000078 MHz for setting 56

About 52 Hz per unit. 52*50 = ±2600 Hz tune range.
I think it's too high for usual TCXO, it will be better to have about 5 Hz per unit.

[TheDefpom]

The step size is dependant upon the output frequency, it is obviously a scaling factor/divisor rather than an offset adjustment, in my case it was only -12Hz off at 80MHz when set to 58.

[radiolistener]

Some teardown.

Front panel:
STM32F103RCT6
Crystal 8 МГц
LCD 3.4"

Frontend:
Xilinx Spartan-6 XC6SLX9
FPGA clock oscillator - 50 MHz
Relay HUiKE HK23F-DC5V-SHG
usb-serial CH340

Other IC's marking is scratched.
It looks like it uses R-2R DAC.

[radiolistener]

The step size is dependant upon the output frequency, it is obviously a scaling factor/divisor rather than an offset adjustment, in my case it was only -12Hz off at 80MHz when set to 58.

yes, I know, but it uses 50 MHz oscillator for FPGA clock.
So, when you set 50 MHz, the output will be exactly the same as FPGA oscillator frequency and you will see the real frequency error of hardware oscillator.

[TheDefpom]

Yep, I did a teardown video segment too, I noticed the same things as you with all the IC's lazered off apart from a couple.

I didn't identify the FPGA oscillator frequency as I couldn't read it at the time without getting it under a microscope.

[radiolistener]

here is fpga oscillator

[mawyatt]

That's a nice looking AWG and the interior looks well done!! Hopefully the waveform performance is also as good!!

Maybe those that have these can do some tests that show the waveform spectral purity and possibly a 2 tone test at a few frequencies?

Best,

[radiolistener]

Maybe those that have these can do some tests that show the waveform spectral purity

Here is spectrum measurement for sine 7 kHz 4 Vpp captured with PC sound card "line in" input at 192 kHz sample rate.
Main spectrum window RBW = 0.7 Hz.

The first picture is background noise of installation (sound card + cable connected to PSG9080, PSG9080 is physically disconnected from mains).


The second picture is 96 kHz span with second harmonic in the receiver bandwidth (2.7 kHz).


The third picture is zoom with first harmonic in the receiver bandwidth (2.7 kHz).

[TurboTom]

Thanks @radiolistener for the teardown and the tests. Considering the price, this "Junktek" thing is really disappointing. Cheap as cheap can...

No dedicated sample memory, R-2R discrete D/A converter, (probably) marginal reconstruction filtering and no shielding at all. The power supply , especially the transformer, doesn't look too trustworthy regarding creepage distances, and performance-wise, -40dBc for the second harmonic is really less than stellar!

This generator may be okay-ish for hobby applications, but if I had to spend 170+ EUR plus possibly import VAT/taxes, I'ld rather spend 60 EUR more (all taxes included) and get Rigol's DG811 and hack it. Despite the size and the toy-like appearance, this will get you a much more mature instrument which can be considered to be the entry into the professional segment. Have a look here for a set of teardown photos of my DG811. It becomes directly obvious that this generator plays in a different league.

If you don't want to spend that kind of money, the Feeltech generators are available for about half the money that the Junktek will set you back, and are pretty well characterized on this forum and, as the common opinion goes, are pretty useful as an entry level hobby AWG (with a mod applied or two...).

[TheDefpom]

I have a feeltech generator, it doesn't compare to this one when it comes to user interface and functionality, I would definately choose the PSG9080 over it, my impressions of it from having one here (my review video and teardown will be published on Wednesday) is certainly very different to yours, yes it has some limitations, but it also has some very nice aspects, the PCB's look well designed to me.

[mawyatt]

Maybe those that have these can do some tests that show the waveform spectral purity

Here is spectrum measurement for sine 7 kHz 4 Vpp captured with PC sound card "line in" input at 192 kHz sample rate.
Main spectrum window RBW = 0.7 Hz.

The first picture is background noise of installation (sound card + cable connected to PSG9080, PSG9080 is physically disconnected from mains).
(Attachment Link)

The second picture is 96 kHz span with second harmonic in the receiver bandwidth (2.7 kHz).
(Attachment Link)

The third picture is zoom with first harmonic in the receiver bandwidth (2.7 kHz).
(Attachment Link)

Was hoping for something better out of a 14 bit 300MSPS DAC at this low a frequency, which will likely get much worse as you go up in frequency.

Thanks for the testing.

Best,

[radiolistener]

It has external power supply connector 5V 3A, so it can be powered from external linear power supply. External power supply can improve performance.

when it comes to user interface and functionality

Yes, front panel of PSG9080 and user interface are excellent and very convenient in use. It is very comfortable to use it.

[mawyatt]

It has external power supply connector 5V 3A, so it can be powered from external linear power supply. External power supply can improve performance.

That's an interesting feature, one could power this from an external battery pack for portable use, however I doubt that an external PS will improved the output signal quality, easy enough to verify tho.

Best,

[JOHN LEE]

As far as I know, the maximum output frequency of DG811 is 10MHz, the sampling rate is 125Msa/S, and there is no programmable function, which can realize automatic output. I found that PSG9080 is grounded during use, which is safer to use. PSG9080 dual-channel maximum output is 80MHz. This price is quite cost-effective. If the requirements for AWG are not high, you can also consider JDS6600. I have a JDS6600 that has been working stably for 2 years. It works very well.