Patent ID: 6567118
Filing Date: 2003-05-20
Classification: H04N

Abstract:
An automatic gain control (AGC) circuit, comprising:an input port for receiving an input signal that is one of a digital input signal and an analog input signal, wherein the input signal at times includes a pilot carrier signal; a circuit coupled to the input port for recovering from the input signal a demodulated video signal; a signal processor coupled to the circuit for providing an adjustment value based upon the demodulated video signal, wherein the signal processor determines which of the digital input signal and the analog input signal has been received by transforming the demodulated video signal into the frequency domain, and wherein, when the input signal is determined to be digital, the signal processor averages the demodulated video signal to generate the adjustment value, and, when the input signal is determined to be analog, the signal processor detects a peak of the demodulated video signal to generate the adjustment value; and an output port coupled to the signal processor for providing the adjustment value.