A channelizing receiver is provided with a plurality of channel receivers for monitoring respective segments of a frequency band being monitored by the channelizing receiver. Each channel receiver includes a channel processor for detecting an electromagnetic signal, measuring the peak amplitude of the electromagnetic signal and comparing this peak amplitude with the peak amplitudes for the electromagnetic signal detected by adjacent channel receivers. Data responsive to a detected signal is transmitted from a channel receiver only if the channel receiver's measured peak amplitude is higher than that for the adjacent channel receivers. The data include an estimate of the frequency and bandwidth of the detected signal made by the channel receiver transmitting the data based upon an assessment of the relative peak amplitudes.