JPS5459015A - Propagation delay time compensating receiver - Google Patents

Abstract

PURPOSE:To reduce the transient answer phase errors of various phase synchronous loops as well as the phase fluctuation of the demodulated data signals, by suppressing the differential propagation delay time at the stage before demodulation. CONSTITUTION:Input PSK modulation wave 20 is branched off (1) into the main signal and the control signal in a proper ratio, and the main signal rceives the delay time of tau1 via delay circuit 2 to be then applied to delay circuit 3. While the control signal receives the delay time of tau0 through delay circuit 4 to be then applied to multiplying circuit 5. The center delay time tau0 of circuit 3 and delay time tau1 of circuit 5-11 are offset by delay time tau0 of circuit 4 and delay time tau1 of circuit 2 respectively, thus standardizing tau0+tau1 to zero. At the same time, tuning circuit 6 extracts the carrier component from the output of circuit 5 and then differentiates the component discriminating circuit 8 via amplitude limit circuit 7. And the slow frequency fluctuation which is contained in the output of circuit 8 via the PSK modulator, the transmission/reception local oscillation and others is eliminated through capacitor 9 with then integration 10. Then the output of the integration undergoes gain adjustment 11 properly to control circuit 3. Thus, the differential propagation delay time can be suppressed for the main signal.