DEMODULATION CONTROL ARRANGEMENT IN SATELLITE COMMUNICATIONS SYSTEM USING 'SCPC-DAMA'

摘要

In order to effectively demodulate an incoming RFsignal which takes the form of bursts in a satellitecommunications system using a Single Channel Per CarrierDemand Assigned Multiple Access (SCPC-DAMA) technique, acontroller is provided which is operatively coupled to adown-converter and a demodulating section. In the eventthat the RF signal is a continuous signal, thecontroller routes an AGC signal, which is outputted fromthe demodulating section, to a first variable attenuatorprovided in the down-converter and applies a constantpotential to a second variable attenuator within thedemodulating section. On the other hand, in the eventthat the RF signal assumes the burst format, thecontroller retains a value of the AGC signal at the timewhen the RF signal undegoes the continuous-burst changeand applies the retained value of the AGC signal to thefirst variable attenuator. The controller further allowsthe AGC signal to be applied to the variable attenuatorwhile the RF signal takes the form of the bursts.