AUTOMATIC GAIN CONTROL FOR WIRELESS RECEIVER

摘要

PROBLEM TO BE SOLVED: To provide techniques for performing automatic gain control (AGC) at a wireless receiver. SOLUTION: The total gain for a wireless receiver is achieved with discrete gain steps for analog circuitry and continuous gain for a digital variable gain amplifier (DVGA) 230. An AGC loop is updated based on power measurements for an output signal from the DVGA. A first gain for the analog circuitry is selected from among multiple discrete gain values based on the AGC loop to maintain the average power of a baseband signal within a predetermined range at input of an analog-to-digital converter (ADC) 220. A second gain for the DVGA is selected based on the AGC loop to maintain the average power of the output signal at a reference power level. The first gain is switched in a manner to avoid saturation of the ADC caused by the baseband signal and to provide switching hysteresis. The AGC may also be performed in log domain and with multiple modes. COPYRIGHT: (C)2011,JPO&INPIT