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measuring low PRI signal

Question asked by superlou on Jul 1, 2007
Latest reply on Sep 5, 2007 by DaveHornbeck
I am attempting to use the MXA with 89601 software to analyze an amplitude instability in my signal. Every so often (it appears to be around 2 seconds but varies) I get some incidental AM, my signal amplitude drops slightly, shifts frequency and then returns.
I would like to measure how often this happens, for how long it happens (each time) and store each incident for further/future analysis.
I am able to set up a level trigger and can use some delay to see the instability for one event. I can also see it happening numerous times as the MXA will trigger repeatedly and show me the instabilities.
What I cannot seem to do is:
1. measure the time gap between each instability, the marker just goes for the length of the acquisition and then resets - it is happening more than 44ms apart and I need the 10MHz span to see the instabilities/spurs so it does not appear that I can do a recording on it (due to events being further apart than max acq length)
2. analyze any instability/trigger event other than the most recent one , even thought I can see them in the spectrogram and can replay them with a playback trigger, I can not seem to setup an AM/FM demod on the earlier events, as soon as I try I just get one acq (I believe it is always the most recent one)
If there were a trigger output, I could trigger a recording/time stamp device to at least let me know the real timing of the events.

I called the subject 'low PRI' signal because it is similar to a challenge I would (and can see in my future) measuring low PRI RF bursts with a wide enough span to do the necessary frequency analysis.

Not sure if I can reduce the span to get the necessary acq length, then increase span during the post-capture analysis - I know I can 'zoom-in' or effectively reduce the span , not sure I can 'zoom out' in frequency domain when doing playback?

Ideas anyone?  

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