Patent ID: 7756502

Claim:
An integrated circuit outputting a digital signal according to a received global positioning satellite (GPS) signal, comprising: a mixer down-converting the received GPS signal into an intermediate frequency signal with a center frequency lower than that of the received signal; a first filter with a pass bandwidth narrower than a bandwidth of the intermediate frequency signal down-converted by the mixer to receive the intermediate frequency signal and to filter the intermediate frequency signal; a second filter removing a signal outside a band of the intermediate frequency signal configured to filter the intermediate frequency signal after the intermediate frequency signal is filtered by the first filter; and a preamplifier between the first filter and the second filter, said preamplifier amplifying the intermediate frequency signal, wherein the pass bandwidth of the first filter is selected based on improving a sensitivity of the integrated circuit defined by: ΔSensitivity=ΔSNR-LS, and wherein: ΔSensitivity represents a variation of the sensitivity of the integrated circuit, ΔSNR represents a SNR variation, and LS represents a signal loss of the first filter.