Electronics > Repair
E4407B Tracking Generator Repair
analogRF:
--- Quote from: smgvbest on October 08, 2020, 11:47:03 pm ---@analogRF
I'm working to trace the circuit out for the PWR_LVL and ALC_MON and others
in the mean time I fired up benchview and took a look at the TG Output at a few levels, I added a strip chart which lets you see whats going on better than just looking at the MIN/MAX values
I'm posting the -10dBm and 3dBm screen caps
What's interesting to me is the dips in the chart are very regular.
--- End quote ---
yeah, these are very interesting and weird. the dips occur almost a little more than 3sec apart regularly but some are very prominent and some
are very tiny which makes it more puzzling.
-10dBm is the same as -2dBm. you should check something like -5dBm or -6dBm and see how flat it turns out.
it would be useful and illuminating if we could have a recording of PWR_LVL, ALC_MON and V1 time correlated with these power graphs.
is it possible that the unit tries to do self alignment of TG every 3 seconds? 3 seconds is normally a lot longer than a normal sweep time of spectrum analyzer when you are using the TG to measure a filter for example, so maybe in an actual measurement these dips occur every let's say 100 sweeps in the dead time at the end of the sweep and if you actually use the TG for measurement you wont see them?! In other words your TG is fine :-\ :o just a thought..
smgvbest:
--- Quote from: analogRF on October 08, 2020, 11:59:13 pm ---yeah, these are very interesting and weird. the dips occur almost a little more than 3sec apart regularly but some are very prominent and some
are very tiny which makes it more puzzling.
-10dBm is the same as -2dBm. you should check something like -5dBm or -6dBm and see how flat it turns out.
it would be useful and illuminating if we could have a recording of PWR_LVL, ALC_MON and V1 time correlated with these power graphs.
is it possible that the unit tries to do self alignment of TG every 3 seconds? 3 seconds is normally a lot longer than a normal sweep time of spectrum analyzer when you are using the TG to measure a filter for example, so maybe these dips occur at the dead time end of each sweep and if you actually use the TG for measurement you wont see them?! just a thought...I don't think what I just described is correct but you never know...
--- End quote ---
I had trouble with Benchview crashing on me when saving the screen caps but here's -8dBm, -7dBm and -6dBm caps
Autoalign is on by default for SA, I will try turning it off and do these again tomorrow and see if it is related.
far as trying to time correlate them. would doing that with a oscilloscope work? I have the Rigol MSO1024 4 channel? but not sure how I would sync them with the power meter in Benchview
analogRF:
--- Quote from: smgvbest on October 09, 2020, 12:12:06 am ---
--- Quote from: analogRF on October 08, 2020, 11:59:13 pm ---yeah, these are very interesting and weird. the dips occur almost a little more than 3sec apart regularly but some are very prominent and some
are very tiny which makes it more puzzling.
-10dBm is the same as -2dBm. you should check something like -5dBm or -6dBm and see how flat it turns out.
it would be useful and illuminating if we could have a recording of PWR_LVL, ALC_MON and V1 time correlated with these power graphs.
is it possible that the unit tries to do self alignment of TG every 3 seconds? 3 seconds is normally a lot longer than a normal sweep time of spectrum analyzer when you are using the TG to measure a filter for example, so maybe these dips occur at the dead time end of each sweep and if you actually use the TG for measurement you wont see them?! just a thought...I don't think what I just described is correct but you never know...
--- End quote ---
I had trouble with Benchview crashing on me when saving the screen caps but here's -8dBm, -7dBm and -6dBm caps
Autoalign is on by default for SA, I will try turning it off and do these again tomorrow and see if it is related.
far as trying to time correlate them. would doing that with a oscilloscope work? I have the Rigol MSO1024 4 channel? but not sure how I would sync them with the power meter in Benchview
--- End quote ---
oh, so they do exist at all levels and always at regular intervals ???
Now I am beginning to think that your TG might be ok afterall.... why dont you try to do a practical measurement/sweep with it? like a filter or an amplifier or even a piece of coax cable. let's say in a 3GHs span or whatever else...
still having time correlated measurements of those 4-5 signals will give a better insight. but I admit it's a bit of a challenge to implement that
at the very least you can record those PWR_LVL, ALC_MON, V1 and I'd also add TUNE with your 4 ch scope in roll mode
and when we put them next to these power graphs, if there is any anomaly happening at 3 sec intervals we know they are correlated with power
dips
analogRF:
just out of curiosity, i cannot find Rigol MSO1024 datasheet anywhere... ???
smgvbest:
--- Quote from: analogRF on October 09, 2020, 12:40:22 am ---just out of curiosity, i cannot find Rigol MSO1024 datasheet anywhere... ???
--- End quote ---
probably because it doesn't exist, what happens when users take their sleeping meds and try to type
Try MSO1104ZS
https://www.tequipment.net/Rigol/MSO1104Z/Mixed-Signal-Oscilloscopes/
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