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

[Mechatrommer]

yes indeed different league... your DG811 is 20MHz @ $300. this Juntek is 80MHz @ $200... i guess to make apple to apple comparison with Juntek (or UTG962), Rigol DG4062 60MHz AWG ($800+) is better suited, imho...

Sure. If you will use it as-is. I know of few to none private users or small businesses who won't consider hacking. Sorry, but IMO your point is ridiculous.

how far can you hack that 125MSa/s device? i dont follow the hack thread sorry. i assume to the max 62.5MHz? do you call 2 points per cycle distortion free pro/business grade? not mentioning the other fun stuffs such as freq resolution when you go near that limit... enlighten me please.

[TurboTom]

The DG811 can be hacked to full DG992 performance (except for amplitude accuracy that drops by about 2dB between 70 and 100MHz -- unless we figure out how it's supposed to be calibrated). The hardware of the models is identical as a common service manual in chinese language, that's surfaced somewhere, proved (same P/N of main PCB). The information that the DG800 series has only 125MSa/s of scan rate is wrong and may have been published in a very early design phase by Rigol. All these units run at 250MSa/s.

Price-wise, I only compared the PSG9080 with the DG811 since in my part of the woods, provided I'ld had to pay full import duties and VAT for the JunTek unit, they would be on par (give or take ten eurobucks). Construction-wise, there is no comparison. Reliability and safety-wise, I trust Rigol's instrument 100% while the PSG9080 could, well, use some improvement...

I agree with you that as a hobbyist's low-cost AWG, the UTG962 appears to be a decent choice.

[Mechatrommer]

The DG811 can be hacked to full DG992

well unfortunately.. its not easily available for sale anymore (ebay)...

[TurboTom]

The DG811 can be hacked to full DG992

well unfortunately.. its not easily available for sale anymore (ebay)...

Really? In Europe, several T/M gear distributors have stock available. Btw, once again, the 125MSa/s specified on the linked page is wrong. All these units sample at 250MSa/s.

Or did you mean to refer to the UTG962 which really appears to be difficult to find meanwhile?

[Mechatrommer]

The DG811 can be hacked to full DG992

well unfortunately.. its not easily available for sale anymore (ebay)...

Really? In Europe, several T/M gear distributors have stock available. Btw, once again, the 125MSa/s specified on the linked page is wrong. All these units sample at 250MSa/s.

Or did you mean to refer to the UTG962 which really appears to be difficult to find meanwhile?

UTG962/932 is newly released sale is not stable yet i guess it sometime come and go... but checking, its currently available in aliexpress (china market, where else?) and many sellers start to selling it there, one is $139 https://de.aliexpress.com/item/4000573960327.html?spm=a2g0o.productlist.0.0.5d833d05WH9iPe&algo_pvid=9a579168-5b1e-4282-88f2-d993b612bae3&algo_expid=9a579168-5b1e-4282-88f2-d993b612bae3-1&btsid=0bb0623016012863212357791e36d5&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

batronix... is euro currency, and its not very friendly to us... well i stand corrected... dg811 also sold in aliexpress $279... https://de.aliexpress.com/item/10000098463394.html?spm=a2g0o.productlist.0.0.c6a635c7RYMVym&algo_pvid=b308c759-b632-44d5-838e-bb0bbecadc8d&algo_expid=b308c759-b632-44d5-838e-bb0bbecadc8d-1&btsid=0bb0624016012866100348760ec1be&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

i was not aware it can be hacked to 100MHz so i stand corrected, but still $200+ is something for me cheers.

[SERJSOCHI]

Hi. I received this generator today. The speaker is very loud, sealed it with tape, now it sounds much better.
What is the best way to remove the gray bumper, as it interferes with placing the device on the shelf.

[radiolistener]

Hi. I received this generator today. The speaker is very loud, sealed it with tape, now it sounds much better.

Nice trick, I think I will do the same, because speaker is really too loud.

What is the best way to remove the gray bumper, as it interferes with placing the device on the shelf.

It is very useful, it allows to put generator on the top of oscilloscope and it don't falling off with help of that rubber bumper.

[jonathanlemoine]

Unless I'm missing something, this doesn't have a 50ohm output. The voltage only lines up with the scope on a 1M input impedance.

[radiolistener]

Unless I'm missing something, this doesn't have a 50ohm output. The voltage only lines up with the scope on a 1M input impedance.

No. I measured the output impedance, it has pretty precise 50 Ohm impedance for all voltage ranges up to 6 Vpp.

I didn't measured output impedance for amplitudes above 6 Vpp, because I'm worry about my RF dummy loads (because they are low power and may be burned out from high power ). But I think it's output impedance the same 50 Ohm up to 25 Vpp.

If you're talking about display value, yes it always displays open output amplitude for internal 50 Ohm impedance. So, you're needs to recalculate it for your load. Since PSG9080 hardware output is 50 Ohm, for 50 Ohm load you can just divide displayed value by 2 to get Vpp (peak-to-peak) amplitude on the load. Or divide displayed value by 4 to get Vpk (peak) amplitude on the load.

Since it displays amplitude for open output, you're needs to apply correction factor for displayed amplitude in order to get Vpp value on specific load:
- for 50 Ohm load Vpp = displayed Vpp * 0.5
- for 75 Ohm load Vpp = displayed Vpp * 0.6
- for 600 Ohm load Vpp = displayed Vpp * 0.923077
- for 1 MOhm load Vpp = displayed Vpp * 0.99995
- for 10 MOhm load Vpp = displayed Vpp * 0.999995

You can look my output impedance measurements here. It is performed with Siglent SDS1102X oscilloscope. With taking into account oscilloscope measurement error, we can see that PSG9080 has pretty precise output impedance 50 Ohm.

PS: just tested impedance with multimeter Brymen BM867:

500 Hz square wave, 1.000 Vpp setting on the generator.
10 MOhm input = 499.76 mV RMS
49.80975 Ohm input (10 MOhm in parallel with [49.77 Ohm + 0.04 Ohm wires]) = 249.20 mV RMS

Calculated output impedance = 50.08 Ohm

[grumss]

I have just purchased one myself (as a toss-around sig gen)

It certainly has "character" but over all its surprisingly handy for its cost.

A few have mentioned that the frequency fine tune doesnt work with the frequency counter... I find that it does but just doesnt align with the generator section! Seems somebody at Junktek has made a "boo-boo" or fudged one of the sections to make things work.. maybe will be fixed with firmware?

Frequency counter sensitivity is low BUT it can also handle 20Vpp according to the manual! - be careful with this one!
Id love to see a amplitude "dbm" button- but can sort of understand why it isnt there.

Overall (so far)- i would recommend- as long ones expectation isnt too high    (it is what it is)

[radiolistener]

A few have mentioned that the frequency fine tune doesnt work with the frequency counter... I find that it does but just doesnt align with the generator section!

what is your firmware/fpga versions?

My one:

Hardware 1.20
Firmware 1.20
FPGA 1.20

[radiolistener]

Frequency counter sensitivity is low BUT it can also handle 20Vpp according to the manual! - be careful with this one!

There is ambiguity for MOD input specification. The manual claims that it has 0...3 V range. But it is used for VCO mode and the same manual claims that VCO voltage range is 0V-5V. So, it's not clear what is voltage range for MOD input.

I tried to test it with 0-5 V and according to ADC values, it looks that MOD input range is 0-5V, but it can see difference even for 5.2 V and above, with non linear code.

[grumss]

A few have mentioned that the frequency fine tune doesnt work with the frequency counter... I find that it does but just doesnt align with the generator section!

what is your firmware/fpga versions?

My one:

Hardware 1.20
Firmware 1.20
FPGA 1.20

Hardware 1.20
Firmware 1.20

Hardware version (on PCB) 1.30

[grumss]

I have just noticed on mine that channel 1 output becomes VERY noisy when i turn on modulation. May have to send it back

[radiolistener]

I have just noticed on mine that channel 1 output becomes VERY noisy when i turn on modulation. May have to send it back

what settings did you used?

[grumss]

I dont remember the settings for this screen shot, but it was noisy like this with all settings

See attachment for channel2 (which is fine)

[radiolistener]

Which frequency did you used for the carrier (for failed screenshot)?

[grumss]

The modulation was 1k /100% and i tested with the carrier frequency from 1Mhz all the way to 80Mhz... Think these screen shots were at a carrier frequency of 10Mhz

[radiolistener]

just tested on my one, both channels works ok (screenshots from the first channel, 10 MHz carrier)

[grumss]

Yep- thats how mine should look as well, i suspect i have a bad solder joint on one of the components... Anyway i have only had it a week or so, im not going to open it up and fix it unless i have to..

I dont think it is typical of the generator, I have just got one that wasnt QCed well enough..

Going through all the "have you followed the instructions?" stuff with the ebay seller as we speak.
(can understand this- but I AM NO BEGINNER

VK3XDK (used to design microwave stuff ... still an easy search on google)

[masterx81]

Interesting device, but i really not like the r-2r DAC 

[radiolistener]

Anyway i have only had it a week or so, im not going to open it up and fix it unless i have to..

You can open and check the PCB. May be there is some flux or solder.
There are just 4 screws and no seal labels.

[gwideman]

In case  it's of interest to readers: 

There's a Koolertron CJDS98 which appears to be the same as this Juntek 9080.

If you download the zip file software and docs package pointed to by the Koolertron vendor on amazon.com, it contains a manual titled PSG9080, and showing a picture of the Juntek.

Of course "same" is relative, as there could well be hardware and firmware variations.

[gwideman]

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,

A significant merit of running it from battery would be to completely avoid ground loops, or the necessity to provide some current path from the sig gen ground to mains earth to avoid half-mains-voltage appearing on the BNCs (albeit at high impedance), as others have discussed.

It's of at least some note that the power supply strategy has changed between the older FY9600/9700 design. Those older ones had a power supply board that produced +/-13.5V and +5V, which were a bit of a pain to replace (see SDG Electronics YouTube series, if interested). 

But this Juntech PSG 9080 has the main PSU board responsible only for providing, one assumes, 5V (thus facilitating the external 5V supply feature), and the other needed voltages are generated on the main DDS+amplifier board.  So that would make replacement of the internal PSU board pretty easy, for those who might want to do that.

Graham

[radiolistener]

yes, you can use USB power bank to power it.
But note it consume about 0.7 A for low voltage output and up to 2 A for 20 Vpp output