| 摘要 |
PROBLEM TO BE SOLVED: To obtain an AM demodulation output only in a desirable wave without being affected by a disturbing wave by subtracting the signal, obtained by setting the amplitude of an orthogonal axis output signal to a specific multiple and shifting the phase by a specific quantity, from the composite signal of an in-phase axis output signal and the orthogonal axis output signal after orthogonal synchronous detection. SOLUTION: From the composite signal of the in-phase axis output signal and orthogonal axis output signal after the orthogonal synchronous detection, the signal is subtracted which is obtained by multiplying the amplitude of the orthogonal axis output signal by√2 and shifting the phase byπ/4+nπ/2 (n=0, 1, 2, 3). This demodulator supplies a received wave including a disturbing wave to a synchronous detector 2 for an in-phase axis and a synchronous detector 3 for an orthogonal axis which constitute an orthogonal synchronous detector 1. Further, the local oscillation signal which is generated by a local oscillator 4 and has the same frequency fc and phaseϕc as the frequency and phase of a desired carrier is supplied directly to the synchronous detector 2 for the in-phase axis and also supplied to the synchronous detector 3 for the orthogonal axis through a -π/2 phase unit 5.
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