CMOS automatic gain control circuit for NEXT series product

Abstract

The invention discloses a NEXT series product CMOS automatic gain control circuit. The automatic gain control circuit is composed of a variable gain amplifier, a fixed gain stage, a peak detector, and a comparator. The variable gain amplifier includes: a VGA main body amplification unit, Common mode negative feedback circuit, DC offset elimination circuit, dB linear converter; variable gain amplifier as the main channel of the intermediate frequency signal, based on CMOS technology, adopts two-stage VGA structure, and connects DC offset elimination circuit after each stage; fixed gain The stage is linked with the variable gain amplifier in one direction, the input transconductance stage adopts a fully differential structure, and the source negative feedback is introduced to provide the absolute value of the gain for the automatic gain control circuit; the peak detector is connected with the output terminal of the circuit and the fixed gain stage, It is used for real-time detection and judgment of signal strength; one end of the comparator is connected to the peak detector and the comparison voltage at the same time, and the other end is connected to the dB linear converter for signal judgment.

Description

technical field [0001] The invention belongs to the specific application in the field of wireless communication circuits, in particular to a CMOS automatic gain control circuit of NEXT series products. Background technique [0002] The development of science and technology is changing with each passing day. In the past ten years, the rapid popularization and upgrading of wireless communication products represented by mobile phones and other wireless device terminals have brought about huge and profound changes in our working methods and lifestyles. Today the wireless communication industry has become one of the largest industries in the world. As the first station of signal receiving and processing, the receiver is responsible for the important tasks of signal extraction, noise reduction, amplification and spectrum shifting. Its performance determines the quality of subsequent signal processing. It is an important application and irreplaceable of analog radio frequency circu...

AI Technical Summary

Problems solved by technology

However, because the AGC control signal is generated through the steps of A / D conversion and digital processing, the feedback adjustment cycle is very long; if the parameters and performance of the automatic gain control loop are to be improved for the task, then its digital processing part is required It should also be adjusted or even redesigned accordingly; and the gain of VGA generally changes in dB steps according to the size of the digital gain control word, and the output of VGA still has a certain range of energy changes.

Images