Circuit for reducing distortion produced by an r.f. power amplifier
US5124665A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 18, 1991 |
| Grant date | Jun 23, 1992 |
| Priority date | — |
| Expiry date | Jan 18, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/0433
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A high frequency SSB radio transmitter has an envelope amplitude modulator for varying the envelope of an r.f. signal source based on an error signal from envelope detectors detecting the envelope of the input and output waveform. It also has a phase modulator for varying the phase of the input waveform based on differences detected in a second amplitude modulator between the instantaneous phase of the input and output r.f. signal. A signal derived from the error signal controls the second amplitude modulator in a subsidiary feedback loop to maintain the size of the envelopes detected by the detectors the same, in order that a difference amplifier may operate effectively. Rapid discrepancies between the detected envelopes occurring within an envelope can then be corrected by the envelope amplitude modulator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.