| 摘要 |
PURPOSE:To compensate non-linear distortion of a repeater loaded on a satellite by an earth station, by receiving a signal of the own station through a satellite by a transmitting station, comparing a demodulating signal of a specific channel in said signal with a transmitting signal, and controlling a distortion compensating circuit of the own station. CONSTITUTION:Input signals from plural signal input terminals 11 of a base station 2 are modulated by modulators 14-14'', and are synthesized by a signal synthesizing circuit 16. To the circuit 16, a non-modulated wave of the i-th channel of about center frequency of a band is inputted from an oscillator 15. An output of the circuit 16 is sent to a satellite repeater 1 through a distortion compensating circuit 17, a transmitter 18 and a transmitting and receiving branching filter 19. An output of the repeater 1 is received by the base station 2, is led to a channel selector 21 through the branching filter 19 and a receiver 20, the i-th channel is extracted by the selector 21, and it is led to a carrier wave-to-noise power ratio (C/N) measuring circuit 22. An output of the circuit 22 is led to a distortion compensating circuit controlling circuit 23, a parameter for deciding a non-linear characteristic of the circuit 17 is controlled so that a C/N value output of the circuit 22 becomes maximum, and non-linear distortion of the repeater 1 is compensated. |
