1370 hipass filter ripple in polA



    lband wide has a filter bank installed after the dewar. There are 9 filters switchable filters:
  1    1370 hipass (ext Input unit. Use with filter 5)

  2    1120-1220
  3    1230-1470
  4    1550-1820
  5    1100-1800
  6    1360-1470
  7    1320 hipass
  8    1180-1280
  9    1280 hipass (ext Output unit. Use with filter 5)

Filters 2-8 can be or'd together (as long as the frequencies don't overlap).
Filters 1,9 are inline switchable before and after  filters 2-8. They always need one of the 2-8 filters inserted to complete the path (usually filter 5).
the lbfb  command can be used to insert one or more filters in the rf path.

the problem:

a2703 on/off ripple in spectral bandpass.

The first set of plots shows  the ripple seen by a2703 on 276oct12 (.ps) (.pdf):

30oct12 testing the 1370 hipass filter looking at total pwr vs time.

On 30oct12 test data was taken, The setup was:
The first set of plots shows total power vs time (.ps) (.pdf)
The 2nd set of plots uses different rf switches for the 1370 hipass filter (.ps) (.pdf)
The these showed that the rf switches that 1370hp filter used seemed to be the problem.

01nov12: install new rf switches for the 1370 highpass filter.

    The rf switches that the 1370hp filter used were replaced.
The plots show the total power vs time with the new  switches (.ps) (.pdf)


processing: x101/121030/ chklbwbar.pro lbw1370.pro lbwdbg.pro, 121101/lbwhpfilter.pro