AFC device for circumference artificial earth satellite communication and frequency converter null for circumference artificial earth satellite communication

摘要

PROBLEM TO BE SOLVED: To separate the frequency deviation of a local oscillator in an artificial satellite and the frequency deviation of doppler shift by means of the motion of the artificial satellite and to highly precisely correct a frequency by providing VCO outputting a frequency reference signal in accordance with the two frequency deviations. ;SOLUTION: First and second phase locked loops(PLL) 121a and 121b are phase-locked with first and second pilot signals which are originated in a pilot signal transmission station and are frequency-converted via the artificial satellite. A frequency counter 122 measures the frequencies of the phase locked loop signals of first and second PLL 121a and 121b. A logic controller 123 separates the frequency deviation of the local oscillator in the artificial satellite and the frequency deviation of doppler shift, which depends on the motion of the artificial satellite, by executing a prescribed operation on the measured value of the frequency counter 122. A voltage control oscillator(VCO) 124 outputs the frequency reference signal in accordance with the two frequency deviations which the logic controller 123 separates.;COPYRIGHT: (C)1999,JPO