Phase compensation for analog gain switching in OFDM modulated physical channel
US7889820B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 2006 |
| Grant date | Feb 15, 2011 |
| Priority date | — |
| Expiry date | Aug 3, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2657
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A control of an amplifier in an automatic gain control (AGC) loop, e.g. in the RF front end circuitry of an OFDM receiver, provides phase adjustment control data to an associated automatic frequency control (AFC), to compensate for a phase jump that would otherwise be caused by switching of the AGC gain between discrete gain states. In the disclosed example, for each gain state, comparators detect a signal energy estimate crossing either a high threshold or a low threshold. Upon threshold crossing, multiplexers select compensation data corresponding to the necessary transition from the prior state to the new state determined by the comparators, based on identification of the prior state and on the particular threshold that has been crossed (high or low). The phase compensation data supplied to the AFC, for one interval corresponding to the timing of the gain switching, adjusts phase rotation implemented in the AFC.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.