| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission power control system by which a C/N measurement time in a satellite communication earth station is shortened, an accurate C/N is calculated to grasp a channel state and transmission power is optimally controlled. SOLUTION: An FM demodulator 3 demodulates a recovered carrier of a digital demodulator 1 using a Costas loop carrier recovery circuit, a level detector 5 detects a level of the demodulated carrier via a low pass filter 4 to measure the S/N. A C/N processing part 6 converts the S/N to on S/N-C/N to obtain the received C/N. A control signal generating part 7 generates a control signal based on the received C/N and the control signal controls transmission power by a transmission power control part 9. The C/N is obtained in a short time and high speed power control is realized. |
