Patent ID: 7463875

Claim:
A radio-frequency (RF) receiver comprising: a 3-step gain-control low noise amplifier stage for amplifying a received RF signal, the 3-step gain-control low noise amplifier stage comprising three low noise amplifiers, each low noise amplifier configured to support a distinct, specified band of RF signals; a switch for selecting one of the low noise amplifiers of the 3-step gain-control low noise amplifier stage; a direct conversion mixer for down-converting an amplified output of said 3-step gain-control low noise amplifier stage, wherein the amplified output corresponds to the low noise amplifier selected by the switch; a variable gain amplifier for amplifying a down-converted output of said direct conversion mixer; and a sigma-delta analog-to-digital converter connected to the variable gain amplifier, wherein the receiver has sufficiently linear operation in the low-noise amplifier stage, direct conversion mixer, variable gain amplifier, and analog-to-digital converter that all transmitter leakage and interferer power can be removed in subsequent digital baseband filter blocks to eliminate the need for additional analog baseband filters.