| 摘要 |
PURPOSE:To suppress out-band spurious at the ON/OFF gate operation of a differential driving type linear modulator, by controlling driving current into a driving circuit for the modulator by a gate signal passed through a low-pass filter. CONSTITUTION:A modulating signal is inputted from a terminal 11 to the driving circuit 1 including a differential amplifier and a differential signal 13 outputted from the circuit 1 is inputted to the differential driving type linear modulator 2 to modulate a carrier wave from a local oscillator 5. An ON/OFF gate signal is inputted from a terminal 15 to a current supplying circuit 3, which supplies driving current to the driving circuit 1. In the current supplying circuit 3, the driving current is controlled by a signal obtained by limiting the ON/OFF gate signal at its band through the low-pass filter 4. |
