Linear amplifier arrangement
US6275685A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1998 |
| Grant date | Aug 14, 2001 |
| Priority date | — |
| Expiry date | Dec 10, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2201/3233
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
This invention relates to high power linear amplifiers. A high power linear amplifier is disclosed for communications such as CDMA communication systems. In accordance with the invention, there is provided a power amplifier comprising a power amplifier, a feedback circuit and a control element; wherein the architecture proposed uses an envelope detector to generate a baseband signal representing the amplitude envelope of the system input RF signal. This is digitised and used to generate phase and gain correction signals. The correction signals modulate the input signal to create a pre-distorted signal: which is applied to the power amplifier for amplification. The pre-distortion is such as to cancel the AM-AM and AM-PM distortion of the power amplifier thus resulting in an amplified output of improved spectral purity. In order to achieve the very high levels of spectral purity required by 3G cellular and multi-carrier 2G cellular systems, the correction coefficients in the lookup table need to be very precisely set. The method proposed incorporates an adaptation system whereby the pre-distorter can `learn` the contents of the lookup table as it operates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.