| 摘要 |
PROBLEM TO BE SOLVED: To provide a two-frequency mixer circuit capable of reducing variations in the output impedance so as to eliminate impedance mismatching with a band pass filter thereby preventing an output signal loss. SOLUTION: A collector of a first transistor receiving a high frequency signal 18 with a first frequency is connected to a collector of a second transistor 6 receiving a high frequency signal 19 with a second frequency, a switching/input matching circuit 34 selects either of local oscillation signals 20, 21 whose third and fourth frequencies differ from each other, provision of a common third transistor 31 receiving both the local oscillation signals 20, 21 with third and fourth different frequencies and provision of a collector output of the common transistor can reduce variations in transistor elements and suppress variations in the output impedance of the mixer circuit. COPYRIGHT: (C)2003,JPO
|
