Augmentation of the frequency selectivity of receiving channels for pulsed-radio-signal detection

The paper proposes a compensation circuit consisting of two mutually out-of-tune resonators and a phase detector that assures a high degree of rectangularity of the resulting amplitude-frequency characteristic and uniformity of the transfer characteristic in the working passband. An expression for the SNR at the output of the circuit is derived; the value of output SNR for the circuit is compared with that for a typical channel consisting of a bandpass frequency converter, a square-law detector, and a lowpass filter.