METHOD AND EQUIPMENT FOR DEMODULATING OF DIGITAL HIGH- FREQUENCY SIGNAL

摘要

PROBLEM TO BE SOLVED: To exactly demodulate a digital high frequency signal with a simplified structure by detecting a binary signal from a period between transitions in positive and negative directions of a rectangular wave IF signal, coupling the signal and unnecessitating synchronization of a carrier wave or a local oscillator. SOLUTION: A receiving signal 121 is formed as a rectangular wave D by a limiting amplifier 200, edges in the positive and negative directions of an IF waveform by a digital filter/intermediate IF edge detecting circuit 600 and signals POSED, NEGED are supplied to each of edge data demodulators 700, 800 in the positive and negative directions. A short-term interval between the edges in the positive and negative directions representing transition of the binary signal and a long-term interval between the successive edges of an IF for the signal D are detected respectively and the signals POST1, NEG1 and POST2, NEG2 are transmitted to an output circuit 900 and synthesized there by each demodulator. In this case, the interval between the edges is corrected by a compensation signal from a frequency compensation circuit 500 by each demodulator.