Receiver for detecting and analyzing amplitude or angle modulated waves in the presence of interference

摘要

This receiver includes in its IF channel a summing network by means of which the output of a calibrated reference oscillator may be added to the received signals. The frequency and amplitude of the reference oscillator are adjusted to match those of a desired one of several co-channel signals which may be simultaneously present in the IF channel. The combined signals are amplitude limited and applied to a frequency deviation detector in which the wide frequency deviations caused by the interaction of the reference and desired signal are detected. The technique can be used to demodulate angle or amplitude modulated signals obscured by jamming signals and to measure the frequency and amplitude of signals which are similarly obscured.