| 摘要 |
<p>A high frequency SSB radio transmitter has an envelope amplitude modulator 3 for varying the envelope of an r.f. signal source based on an error signal from envelope detectors 5, 6 detecting the envelope of the input and output waveform. It also has a phase modulator 4 for varying the phase of the input waveform based on differences detected in phase detector 10 between the instantaneous phase of the input and output r.f. signal. A signal derived from the error signal controls an amplitude modulator 10 in a subsidiary feedback loop to maintain the size of the envelopes detected by detectors 5 and 6 the same, in order that difference amplifier 7 may operate effectively. Rapid discrepancies between the detected envelopes 5 and 6 occurring within an envelope can then be corrected by amplitude modulator 3. <IMAGE></p> |
