A method and system is disclosed for providing an automatic gain control in signal processing. After receiving a stream of analog signals, a gain is adjusted on the received analog signals using a first set of gain compensation parameters. Then, the adjusted analog signals are converted to digital signals. A predetermined number of digital signals are collected from the converted digital signals within a predetermined time period. The collected digital signals are delayed from being transferred out for further demodulation processing for a predetermined delay time. At the same time, a second set of gain compensation parameters are estimated based on the collected digital signals. The estimated second set of gain compensation parameters are applied to the delayed digital signals.