| 摘要 |
PURPOSE:To suppress a local oscillation signal leaked from an output section without use of a filter eliminating the leaked local oscillating signal for the output section of a transmission frequency converter. CONSTITUTION:The circuit is provided with a local oscillator 1 generating a local oscillating signal, a distributer 2 branching the local oscillating signal, a mixer 3 receiving one of the branched local oscillating signals by the distributer and mixing the signal with an intermediate frequency signal, a variable phase shifter 4 and a variable attenuation device 5 respectively adjusting a phase and an amplitude of the other branched local oscillation signal at the distributer, a combiner 6 combining the local oscillating signal leaked from the mixer with the local oscillation signal via the variable phase shifter and the variable attenuation device, a level detector 7 detecting the level of the combined signal, and a controller 8 receiving a detection output of the level detector and controlling the variable phase shifter and the variable attenuator. |
