| 摘要 |
PURPOSE:To attain a circuit having excellent separation between a high frequency reception signal and a local oscillation signal and a good characteristic with a simple circuit constitution, by using a transistor (TR) or an FET as a mixer element. CONSTITUTION:In Figure, since a resistor 34 and a series circuit comprising a line 35 having 1/4 wavelength at the local oscillating signal frequency fL band and a high frequency short-circuit capacitor 36 are connected in parallel between an emitter of a TR33 used as the mixer and ground, the fL is given from the emitter efficiently and the TR acts like a low noise amplifier at the intermediate frequency bnad fIF. Further, since an input reception signal fR is given from the base and the fL is from the emitter, the separation of the signals fR and fL is done in excellent way. |
