| 摘要 |
PURPOSE:To take a sufficient conversion gain even when the amplitude of an input signal is small by providing a differential amplifier circuit amplifying an input signal and inputting the result differentially to a double balanced type multiplier circuit so as to attain ease of circuit integration in a mixer circuit comprising the double balanced type multiplier circuit. CONSTITUTION:RF terminals 35, 36 and LOCAL terminals 37, 38 of the double balanced type multiplier circuit form respectively differential input terminals. Further, no coupling capacitor is given to the input of the double balanced type multiplication circuit, instead a K-differential amplifier circuit and an emitter follower are provided. The differential amplifier circuit consists of collector load resistor 21, 22, transistor 23, 24 and a constant current source 25. The differential amplifier circuit amplifies an input signal vi to the input terminal 1 by m-time and gives outputs of two complementary signals m.vi and m.(-vi). Thus, the coupling capacitor difficult for circuit integration is not required and the converting gain is ensured sufficiently large.
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