Patent ID: 8295380
Filing Date: 2012-10-23
Classification: H03G,H04L

Abstract:
1. An automatic gain control (AGC) circuit for an orthogonal frequency-division multiplexing (OFDM) receiver comprising: a signal power measuring unit configured to measure signal power of input digital signals that are derived from incoming data frames with preambles, the signal power measuring unit being configured to produce gain change signals when the signal power differs from a reference target power level; a finite state machine operably connected to the signal power measuring unit to receive the gain change signals, the finite state machine being configured to change the gain of an amplifier of the OFDM receiver in response to the gain change signals until a preamble of the data frames is detected for the first time, the finite state machine being further configured to change the gain of the amplifier in response to the gain change signals, after the preamble is detected, only during periods when the preambles of the data frames are being processed by the OFDM receiver such that the gain of the amplifier is not changed during periods when other portions of the data frames are being processed by the OFDM receiver; and at least one additional signal power measuring unit, each of the signal power measuring unit and the at least one additional signal power measuring unit being connected a receiver chain, the finite state machine being a synchronous MIMO finite state machine configured to control the signal power measuring unit and the at least one additional power measuring unit and to receive the gain change signals from the signal power measuring unit and the at least one additional power measuring unit.