US 2006/0217094 A1 · Automatic gain control device

Abstract

A received signal level is detected in each of a wide band, middle band, and narrow band and each detected signal is converted to a digital signal. A DSP 18 determines the enabled/disabled state of an LNA 3 and an attenuator 4 as well as a gain adjustment amount based on the signal level of each band. For example, the gain adjustment is not performed when the signal level of the narrow band including a desired frequency is not larger than a prescribed value even the signal level of the wide band or middle band is larger than a prescribed value. When the signal level of the narrow band is larger than the prescribed value exceeding a gain adjustable limit level in the attenuator 4, the gain of the LNA 3 is adjusted, while maintaining the gain adjustable amount in the attenuator 4 around the limit level, to reduce the gain as a whole.

Claims12

Dependent claims

An automatic gain control device, comprising:

first gain adjustment part for amplifying the gain of a received signal;
second gain adjustment part for reducing the gain of said received signal;
level detection part to detect levels of said received signal in each of a plurality of frequency bands;
A/D converter to convert level detected signals in each band detected by said level detection part to digital signals;
and
digital signal processor to determine the enabled/disabled state of the gain adjustment by said first gain adjustment part and said second gain adjustment part and a gain adjustment amount based on level detected digital signals of each band outputted from said A/D converter.

3 more elements

Dependencies are inferred from the claim text.

Automatic gain control device

Life of this patent

Automatic gain control device

Life of this patent

Abstract

Claims12