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Receiver and IFs

receiver = <receivercode>
   ! this selects what collimation parameters to use, and specifies
   ! which receiver the LO power is routed to.  (My understanding is
   ! that only one receiver at a time receives LO power.)

firstlo = <first LO frequency in GHz>

phasemod1 = <NONE | SINE | WALSH >
   ! specifying the functional form of the phase modulation imposed on
   ! the first Local Oscillator.  May also want to specify the order of
   ! the Walsh function, although letting it be implied by the number of
   ! available antennas is probably OK.  The suffix 1 indicates that it 
   ! is applied to the first LO.
   ! I include this technical detail in the script because I'm quite 
   ! unsure that we can a priori make the right choice that will work
   ! for everything.

phasemodrate1 = <modulation rate in Hz>
   ! Basic modulation rate (repetition of the Walsh functions, or lowest
   ! harmonic for the sine waves).  Each antenna will have a sequency or
   ! harmonic number of it's own.
   ! If WALSH is selected, there will be interesting constraints on permitted
   ! rates

firstlodoppler = <OFF | SET | SETREF | TRACK | TRACKREF >
   ! SET = set LO at scan beginnings
   ! TRACK = track continuously during scan
   ! REF = set LO at mosaic center; otherwise at mosaic offsets
   ! If not OFF, firstlo frequency is barycentric

dopsource = <source descriptor | CURRENT>
   ! Use given source descriptor to calculate doppler, rather than current
   ! source (to observe bandpass calibrator at same frequency as main field)



Kate Weatherall
2000-03-08