| 摘要 |
PURPOSE:To obtain an AM demodulation signal with high linearity by using an orthogonal biphase clock so as to apply phase detection thereby obtaining a root of square sum of two phase detected outputs. CONSTITUTION:An amplitude modulation wave given to an input terminal IN is divided into two signals through a delay circuit DL and an inverse amplifier AMP11. The two AM signals are fed to the 1st and 2nd phase detectors PD11, PD12. Switches SW11, 12 and SW13, 14 are driven by signals Q1-Q4 whose phases are shifted with each other by 90 deg. each and apply synchronous detection the outputs of the circuit DL and the amplifier AMP11 to output phase detection outputs v90 deg., v0 deg.. A digital computing element DCA applies the operation of the root of square sum of the outputs v90 deg., v0 deg..
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