Products > Test Equipment
JunTek PSG9080 Programmable Signal Generator (80 MHz - 300 MSa/s - 14-bit)
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:
--- Quote from: SERJSOCHI on October 03, 2020, 07:53:36 pm ---Hi. I received this generator today. The speaker is very loud, sealed it with tape, now it sounds much better.
--- End quote ---
Nice trick, I think I will do the same, because speaker is really too loud. :)
--- Quote from: SERJSOCHI on October 03, 2020, 07:53:36 pm ---What is the best way to remove the gray bumper, as it interferes with placing the device on the shelf.
--- End quote ---
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:
--- Quote from: jonathanlemoine on November 07, 2020, 01:34:27 pm ---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.
--- End quote ---
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)
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