PURPOSE: To obtain compact constitution suitable for a communication satellite by performing the frequency control of a local oscillator in a period multiplied by integer times the time slot in case of transmitting a signal to a time-divided time slot synchronized with plural frequencies.
CONSTITUTION: The oscillation frequency of an oscillator 11 capable of changing the oscillation frequency for plural transmission frequencies is controlled by a control circuit 15. Also, by controlling a buffer circuit 2 by the circuit 15, synchronization with the time slot for communication is taken, and the frequency is changed in the period of the integer times the slot, and transmission is stopped. The oscillator 11 is constituted of a frequency synthesizer and the circuit 15 is operated synchronizing with the output of a synchronous circuit 17 synchronized with the time slot at a program control circuit. By storing arrival information in the circuit 2 during the stoppage of the transmission, the communication can be continued. In such a way, it is possible to miniaturize a local oscillation circuit.
SEKI KAZUHIKO
SHOMURA TATSURO
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