| 摘要 |
PURPOSE:To simplify the circuit and to prevent the deterioration in the S/N ratio due to detour from a power supply, by forming a bias power supply required for a high frequency amplifier, through the rectification of a part of an oscillation power of a local oscillator. CONSTITUTION:A positive power supply +B is applied to a local oscillator 12 and a low noise high frequency amplifier 11 or the like. The local oscillator 12 is activated through the positive power supply +B. An oscillation output of the local oscillator 12 is applied to a mixer 14 and a part of the output is split and applied to a rectifying circuit 13 to generate a negative voltage. This negative voltage is applied to the high frequency amplifier 11 as a negative bias -V. Thus, a part of the local oscillation power is rectified and used for the bias power supply of the amplifier, then a device which is simple and has an excellent S/N ratio can be obtained. |
