Patent ID: 8184048

Claim:
A dual mode satellite signal receiver capable of supporting at least two global navigation satellite systems, the dual mode satellite signal receiver comprising: a frequency synthesizer operative to generate a local oscillator signal based on a reference frequency wherein the frequency synthesizer is capable of supporting multiple reference frequencies; a mixer operative to mix the local oscillator signal with a satellite signal and outputting a mixed signal where the mixed signal comprises a signal in an intermediate frequency band; a first filter operative to filter the mixed signal to reject an image signal and output an actual signal; a second filter operative to filter the actual signal received from the first filter to output a signal in a predetermined bandwidth based on a mode of the receiver; and a variable gain amplifier operative to amplify the signal received from the second filter to a predetermined level and output the amplified signal, wherein the variable gain amplifier comprises and which comprises an exponential current generator operative to generate a first current and a second current such that a ratio of the first current to the second current varies exponentially to a linear-gain-control voltage received from an automatic gain control loop; an exponential current-to-voltage converter operative to convert the first current and the second current into voltages; and an amplifier operative to amplify an input signal by a gain based on the voltages from the exponential current-to-voltage converter.