RF transmitter with variably biased RF power amplifier and method therefor
US7570931B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2006 |
| Grant date | Aug 4, 2009 |
| Priority date | — |
| Expiry date | Feb 7, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/045
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An RF transmitter (30) includes an RF power amplifier (32) for which the power input bias voltage (40) and signal input bias voltage (80) are controlled within feedback loops. A peak detector (44) generates a lowered-spectrum, peak-tracking signal (34) that follows the largest amplitude peaks of a wide bandwidth communication signal (16) but exhibits a lower bandwidth. This signal (34) is scaled in response to the operation of a drain bias tracking loop (146) then used to control a switching power supply (36) that generates the power input bias voltage. The tracking loop (146) is responsive to out-of-band power detected in a portion of the amplified RF communication signal (16″). A ratio of out-of-band power (128) to in-band power (126) is manipulated in the tracking loop (146) so that the power input bias voltage is modulated in a way that holds the out-of-band power at a desired predetermined level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.