Analog multiplexer and variable gain amplifier for intermediate frequency applications

摘要

A diversity receiver circuit system including a primary channel (20) and a diversity channel (22), where analog input signals are converted to differential signals in both channels (20,22). The receiver circuit system includes a multiplexer (14) and a variable gain amplifier (12) formed on a single RF integrated circuit chip (16), where the multiplexer (14) is positioned before the amplifier (12). The differential signals in the primary channel (20) and the diversity channel (22) are applied to an amplified path (72,78) and a non-amplified path (76,82) in the multiplexer (14). A control signal selects one of the amplified primary channel signal, the non-amplified primary channel signal, the amplified diversity channel signal or the non-amplified diversity channel signal. The selected signal is then applied to a first amplifier stage (88) and a second amplifier stage (96) in the variable gain amplifier (12), where both amplifier stages (88,96) include an amplified path (90,98) and a non-amplified path (92,100). <IMAGE>