| 摘要 |
PURPOSE:To reject the mixing of PM component in an AM detection section through avoiding the PM component included in signals of intermediate frequency component, by PM-modulating the signal of local frequency with the demodulated PM component at the PM detection section and mixing down it with the reception signal. CONSTITUTION:A signal via a high frequency amplifying stage RF and an output from a VCO of a frequency synthesizer 9 are mixed at a mixer 1, the signal in intermediate frequency is outputted, it is in PM detection at a phase detector DET2 to output a difference signal 11 of both left and right channels. This signal 11 is inputted to a balanced modulation circuit BM with the output signal 10 of the VCO, and a modulated signal 12 is outputted. A signal 13 phase-shifted by pi/2 is outputted from a shifter PS, the signals 12, 13 are added at an adder AD and added to a limiter LIMITER as a signal 14. A signal 16 rejecting the amplitude component and a reception signal 15 are multiplied at a mixer MX2 to output the intermediate frequency signal rejecting the PM component from the mixer MX2. |
