| 摘要 |
PURPOSE:To reduce the number of times of transmission of a compensation signal to a permissible extent with regard to the operation of the satellite, by providing a reference frequency generator capable of making frequency compensations such as a voltage-controlled crystal oscillator (VCXO) and a frequency synthesizer in a satellite. CONSTITUTION:An earth station 22 receives a reference frequency signal (fs) from the artificial satellite 21 on the ground and a comparing device 11 compares it with a stable frequency signal from a cesium atom oscillator 10; and computer 12 calculates the time variation rate of the signal f(s) in detail to estimate future variation of the fs, and calculates a correction time, an interval, and correction information to transmit the correction information to the artificial satellite 21. The control circuit 2 of the artificial satellite 21 supplies a fine correction digital value to a D-A converter 3 at adequate fine time intervals on the basis of the timer signal in the satellite and the correction information and the result is sent to the voltage-controlled crystal oscillator 4 to correct the fs generated therein momentarily, so there is no trouble to the operation of the artificial satellite and an extremely stable reference frequency signal is obtained. |
