mclineParticipantmcline August 25, 2020 at 2:57 pm
I am generating a step sweep of 824MHz to 849MHz at -20db with 4000 points and a dwell time of 5ms on a VSG60 and feeding this signal into the BB60C. When viewing the signal on the Spike software, the signal has about a .5db “ripple.” Is this normal behavior for the BB60, or Spike software? If not, could you explain the reason I’m seeing this issue, and how I might mitigate it.
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Justin CrooksModeratorJustin Crooks August 26, 2020 at 11:04 am
Michael, this looks like the 140 MHz SAW band pass filter in the BB60C. Most of the ripple should generally be removed in our corrections, but there can sometimes be a little residual ripple which is somewhat worse as the device is warming up. Once the BB60C is fully warmed up, this ripple may be smaller.
Hopefully this helps. If you are looking for amplitude deviations smaller than 0.5 dB, you may need to wait for the device to warm up for 30 minutes, and then use trace math or some other mechanism to subtract out this baseline trace.
For what it’s worth, you should not see this ripple in the SM200B/C. We do not use any SAW filters, so the IF is smooth.
mclineParticipantmcline August 26, 2020 at 1:21 pm
Justin, thanks for the quick response.
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