| 摘要 |
PURPOSE:To realize output impedance matching for an intermediate frequency signal over a wide band and to make the matching independent of the circuit shape at a high frequency signal side by providing an intermediate frequency signal blocking circuit on a main line near a mixer diode in a mixer using a plane circuit, grounding and short-circuiting the other end of the diode and connecting a low pass filter to the said main line. CONSTITUTION:The intermediate frequency signal blocking circuit 19 is a circuit showing a passing characteristic to a high frequency signal and a local oscillation signal and showing an open impedance to an intermediate signal and provided on the main line 12 near a mixer diode 13. Thus, the effect of the circuit at the high frequency signal side connected to a terminal 11 and the circuit provided on the main lie on the output matching state at the intermediate frequency signal is avoided. Since a terminal C of the diode 13 is connected directly to a grounding conductor of the main line 12, the parasitic impedance caused at grounding is decreased and the output impedance matching over a wide intermediate frequency signal band is realized. Further, a matching line 12' acts like a matching circuit element having nearly the same degree of capacitance as a termination open stub of an LPF 16 when viewing the diode 13 from an intermediate frequency signal output terminal 18.
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