A circuit and method is provided for determining the frequency of a signal of interest in a wideband composite RF signal. An analog preprocessor is configured to receive a composite RF signal from an antenna and produce bandlimited frequency sub-bands S1 to Sn. An image converter is configured to receive and alias the bandlimited frequency sub-bands S1 to Sn to baseband and generate a first alias-band output signal and a second alias-band output signal. A processor is configured to receive the two alias-band output signals and determine the frequency shift of the signal of interest between the two alias-band output signals and calculate the frequency for the signal of interest using the frequency shift.