| 摘要 |
PURPOSE:To detect beats with high precision by adding opposite phase outputs of cascaded differential amplifiers and rectifying the sum. CONSTITUTION:The full-wave rectifier of the (n)th stage consists of transistor (TR) Qn01-Qn06 and Qn03-Qn06, resistances Rn01, Rn02, Rn1-Rn2m, and constant current sources I0n, In1-Inm (n, m: positive integer). Then an adding circuit 2 equipped with TRs Q003-Q005 adds the opposite-phase outputs of the full-wave rectifies of the 1st - the (n)th stages, a capacitor C003 removes a carrier component of IF, and a capacitor C002 removes an AC component completely. The output is supplied to a full-wave rectifier, and a beat component and a multipath component are rectified and detected, and smoothed by a resistance R006 and a capacitor C004, so that a beat detection voltage VBEAT is outputted.
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