Demodulation control arrangement in satellite communications system using 'SCPC-DAMA'

摘要

In order to effectively demodulate an incoming RF signal which takes the form of bursts in a satellite communications system using a Single Channel Per Carrier Demand Assigned Multiple Access (SCPC-DAMA) technique, a controller (40) is provided which is operatively coupled to a down-converter (10) and a demodulating section (12'). In the event that the RF signal is a continuous signal, the controller routes an AGC signal (51), which is outputted from the demodulating section, to a first variable attenuator (14) provided in the down-converter and applies a constant potential (44v) to a second variable attenuator (24') within the demodulating section. On the other hand, in the event that the RF signal assumes the burst format, the controller retains a value of the AGC signal at the time when the RF signal undegoes the continuous-burst change and applies the retained value of the AGC signal to the first variable attenuator. The controller further allows the AGC signal to be applied to the second variable attenuator while the RF signal takes the form of the bursts.