A method is provided for individually processing multiple frequency bands in a composite RF signal is disclosed. The composite RF signal is separated into a plurality of gain controlled and bandlimited frequency bands. The gain controlled and bandlimited frequency bands are then recombined to produce a controlled composite RF signal, which is then digitized by undersampling with an ADC to produce a plurality of unambiguous frequency bands convolved around baseband. The sample frequency can be substantially less than the Nyquist Limit of twice the highest frequency present for digitization. Each baseband signal is monitored for amplitude spikes therein. In response to an amplitude spike, the appropriate frequency band is modified by a control signal to hold the ADC to within its dynamic range.