METHOD AND DEVICE FOR RECEIVING HIGH FREQUENCY SIGNAL

摘要

PROBLEM TO BE SOLVED: To eliminate the effect of a local oscillation signal on an RF signal to be demodulated and to improve the accuracy of demodulation by separating a 1st input port from a 2nd input port by a two-port non-reciprocal separation circuit. SOLUTION: An N port coupled circuit 1 has a 1st input port 2 and a 2nd input port (output port) 3 and is a five-port coupled circuit provided with an active separation circuit 13 being a two-port non-reciprocal separation circuit functioning as an isolator. The circuit 13 is connected between a passive 3-port circuit 12 and a passive 4-port circuit 14. Then, the port 2 is separated from the port 3 by the circuit 13. Thus, a 1st RF signal to be demodulated is separated from a 2nd RF signal generated by a local oscillator, and the effect of a local oscillation signal on the RF signal to be demodulated is eliminated so that demodulation accuracy can be improved.