| 摘要 |
PURPOSE:To cope with doppler fluctuation by means of a small capacity buffer by detecting the doppler fluctuation of a clock depending on the fluctuation of the position of a satellite and sending a signal while using the clock fluctuat ed in the reversing direction in advance by the fluctuation. CONSTITUTION:Since the doppler quantity is a length fluctuation per time, the doppler quantity is detected from a holding circuit 11 and a subtracter 12 operated at each frame clock by using satellite distance information, the doppler quantity is converted into an instantaneous phase shift by a converter 3 to control a phase shifter 2. The converter 3 is so constituted that the dopper quantity being subject to multiplicaton of a constant by a ROM table 31 is accumulated integratingly by an adder 32 and a holding circuit 33 operated at a prescribed period. The phase shifter 2 controls the phase of a clock recovered by a demodulator 4 to correct the doppler fluctuation. The clock obtained in this way is used, as a transmission clock.
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