SYSTEM FOR COMMUNICATION IN ANALOG OR DIGITAL MODE MOBILE STATION EMPLOYING THE SAME

For use in a system capable of communicating in either analog or digital wireless infrastructures, an intermediate frequency ("IF") amplifier and method that allows the system to process both analog and digital input signals in a common amplifier stage. The system includes: (1) first and second amplifiers, having parallel-coupled signal inputs and gains that combine to equal a constant total value, that receive an input signal and produce therefrom first and second output signals that are each a function of an applied gain signal, (2) a combinatorial circuit, coupled to the first and second amplifiers, that derives from the first and second output signals a combined signal that is a function of a power of the input signal and substantially immune to changes in the applied gain signal and (3) a gain control circuit, coupled to the first and second amplifiers, that holds the gain signal constant when the input signal is analog and varies the gain signal when the input signal is digital.