Patent ID: 6831957
Filing Date: 2004-12-14
Classification: H03G,H04H

Abstract:
A method of implementing dual mode automatic gain control for a digital radio receiver, the method comprising the steps of:(a) providing a RF broadcast receiver having an IF gain controlled amplifier (GCA), a programmable gain amplifier (PGA), a digital automatic gain control (AGC) configured to control GCA gain and PGA gain in response to at least a digital output code that is determined partially by PGA output signal strength, at least one low noise amplifier (LNA), at least one down converter (Mixer), and an analog AGC configured to control LNA gain and Mixer gain in response to at least a GCA input signal; (b) providing a gain control register having a LNA control bit, a Mixer control bit, a GCA control bit, and a PGA control bit; (c) resetting the gain control register bits to an initial state; and (d) adjusting LNA gain and Mixer gain via the analog AGC in response to the control register bit setting and the GCA input signal and further adjusting GCA gain and PGA gain via the digital AGC in response to the control register bit setting and the digital output code such that the LNA gain, Mixer gain, GCA gain and PGA gain combine to render the RF broadcast receiver capable of maximizing its signal-to-noise ratio and linearity to accommodate reception and amplification of L-band signals and band-III signals.