Feedforward amplifier with improved characteristics without using pilot signal
US6133791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1998 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Oct 23, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/3229
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A feedforward amplifier which includes a distortion detector, a distortion eliminator, an error power extractor, a first level detector and a first controller. The error power extractor extracts output error power due to variations in the distortion eliminator by combining the output signal from the distortion eliminator with the signal from a first linear signal path in the distortion detector in opposite phases. The first level detector detects the output error power extracted by the error power extractor, and the first controller controls a first variable attenuator and a first phase shifter which are interposed in the distortion eliminator such that the output error power is maintained at zero. This can solve a problem of a conventional feedforward amplifier in that the power level of the pilot signal must be increased to heighten the detection sensitivity of the pilot signal because the detection level of the pilot signal becomes minimum at an optimum operation point, and that the increasing power of the pilot signal degrades the communication quality of a system employing the conventional feedforward amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.