Feed forward amplifiers and methods
US5808512A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1997 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Jan 31, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/3235
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Feed forward amplifiers and methods particularly suited for power multichannel microwave amplifiers for cellular phone base stations and the like. The input signal is modulated with a small percentage of modulation at a relatively low frequency before being amplified by the main amplifier. At the same time, the input signal is also coupled to provide inphase and quadrature components thereof to be mixed with the amplifier output and lowpass filtered to extract a component of the low frequency responsive to modulation components in the amplifier output due to the low frequency modulation. This signal is then multiplied by the low frequency to provide a DC voltage controlling an adaptive control circuit to adjust the inphase and quadrature components of the intermodulation components and the low frequency modulation of the entire signal so that the result can be combined with the main amplified signal to remove the intermodulation components and the low frequency modulation of the entire signal from the amplifier output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.