Method and device to control the gain of a radio receiver

摘要

An automatic gain control (AGC) method and system for a radio receiver are proposed in which the ACG comprises two AGC loops; a first loop controlling signal gain in the analogue portion of the radio receiver, a second loop controlling gain in the digital domain after digitization of the received signal. The analogue AGC loop has a slower response time than the digital AGC loop. When applied to a multi-branch diversity receiver, each branch has its own digital AGC loop, but the analogue gain can be common to all branches, based on measurement of the analogue signal in each branch.

主权项

1. An Automatic Gain Control system for a radio receiver having at least one receiving signal path with an analogue and a digital portion, the Automatic Gain Control system comprising:
at least two Automatic Gain Control loops; wherein at least one first Automatic Gain Control loop comprises a first AGC circuit and is configured to initially control the gain of at least one signal amplifier located in the analogue portion of the receiver and thereafter to control the gain of the at least one signal amplifier located in the analogue portion of the receiver only upon detection of a change in reception conditions that satisfies predetermined criteria; wherein at least one second Automatic Gain Control loop comprises a second AGC circuit and is configured to control the signal amplification of the at least one signal processing unit in the digital portion of the receiver; and wherein the digital portion of the receiver operates on a digitized receiving signal that is a digitized form of an amplified analogue receiving signal produced by the analogue portion of the receiver.