Sweep generator setup help - Page 1
Forum section: electronics / projects

author: ttx450
author_rank: Regular Contributor
timestamp: February 02, 2024, 12:02:31 am
content: Hi, I am still at it trying to figure out if my juntek psg9080 can do the right kind of sweep. So far I have been unsuccessful. Looking for any advice as I might not have the scope or AWG setup right.I have the 9080 setup to sync out & have the sync out turned on. In the soft menu I have sweep set to start 400Hz & end 1,000Hz, set to 2 sec, sweep direction increasing and sweep mode to line using a sine wave.Scope Ch1 input from sweep and Ch2 is receiving the sync output from the AWG. I have the scope to trigger on CH2.If you look at the screenshot, looks to be triggering off every sine wave and not like in the 2nd picture. Where it triggers once and then several sine waves and starts over. Is this a setup error? Thks..p.s. the manual for the juntek psg9080 is very poor.

author: moffy
author_rank: Super Contributor
timestamp: February 02, 2024, 01:51:40 am
content: You could try a much faster sweep time so that you could see a full sweep on the oscilloscope display just to confirm that the signal generator is sweeping. It's hard to tell whether the frequency is sweeping or fixed because of the long sweep time.

author: donlisms
author_rank: Frequent Contributor
timestamp: February 02, 2024, 02:37:58 am
content: I'm not familiar with your 9080, but maybe I can generalize. I know there are two basic kinds of sync, one that gives a pulse for every wave, and one for sweep mode that gives the start (and end) of the sweep, covering many waves during that time.If I use the latter, and feed it into the trigger circuit of my scope somehow, I want the scope sweep time to be about two seconds if the generator sweep time is about two seconds.At such a low rate, the scope will want a rather long trigger reset time, so there may be a noticeable gap between displayed sweeps.The other thing I might do is go the other direction. My generator can take a trigger input to start a sweep, and so can my scope. So if I can create a trigger in some other way, I can trigger both my generator's sweep and the scope's sweep with that same signal.

author: ttx450
author_rank: Regular Contributor
timestamp: February 02, 2024, 11:36:39 pm
content: Thanks for the help. Picture shows sweep running and triggering on every wave? My AWG is set to have a start freq 400Hz and end 1,000Hz.I cant get the full sweep to display yet on the scope. Just part of it. I am learning so dont know either one too well.Appreciate any help. Thks..p.s. Trying to find a device that is able to sweep FM circuits and I am not sure the 9080 will do that?

author: CaptDon
author_rank: Super Contributor
timestamp: February 03, 2024, 12:52:46 am
content: Well, an obvious observation, if you want to see the whole sweep then the time to generate the horizontal sweep should match time to do the frequency sweep. You stated 2 seconds. you might try single sweep mode and 200 milliseconds per division giving a total trace time of two seconds.The scope will capture one complete horizontal sweep and stop until you manually reset 'single sweep' and it will wait for another sync pulse.

author: ttx450
author_rank: Regular Contributor
timestamp: February 03, 2024, 06:45:10 pm
content: Hi, when I set the scope at 200 ms I can barely see the sweep wave (I can see the full sweep wave), its pretty much green bar with a slight, very faint sine wave embedded in it. Is there a way to bring this out better to view? Or is this the way it will look if I want to see the whole sweep? Also, the triggering is all one bar at 200 ms and no visible square wave.Its looking like the 9080 is sending a trigger on every wave as "donlisms" mentioned, is there a way to change this? Appreciate the help thks..