| 摘要 |
PURPOSE: To reduce the distortion which is caused at the time of using a high frequency power amplifier, which is not dedicated for SSB. CONSTITUTION: A high frequency SSB radio transmitter is provided with an envelope amplitude modulator 3, which change the envelope of a high frequency signal source based on error signals from envelope detectors 5 and 6 which detect enveloped of input and output waveforms, and is provided with a phase modulator 4 which changes the phase of the input waveform based on the momentary phase of the error signal. Signals taken out from error signals approximately keep the magnitudes of envelopes detected by detectors 5 and 6 for the purpose of effectively operating a differential amplifier 7 and control an amplitude modulator 10 in an auxiliary feedback loop. The quickly varying difference between envelopes detected by envelope detectors 5 and 6 forms one envelope, and it is corrected by the amplitude modulator 3 thereafter. |
