| 摘要 |
PROBLEM TO BE SOLVED: To provide a mixer circuit that can maintain an excellent image rejection characteristic against dispersion of the constants of circuit elements and maintain performance for other signal characteristics equal to or better than that of a conventional mixer circuit. SOLUTION: To the input side of a local signal Slo and the output side of an IF signal Sif , 90-degree phase shifters 10, 50 consisting of 2-stage configuration polyphase filters are provided. A signal final output stage is provided with an emitter follower type output circuit 51 to compensate a signal power loss by the high impedance of the 90-degree phase shifter. A frequency conversion section has a configuration of a Gilbert mixer where an amplifier section 40 is used in common. Signal distribution resistors R1-R4 are provided into the transmission line of reception signals Srf 1, Srf 2 between the amplifier section 40 and mixer sections 20, 30, and the degradation in the image rejection characteristic due to the common use of the amplifier section 40 is prevented.
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