Microwave Receiver Having Coherent Threshold Detection

Patent Number: 5,455,845
Date of Patent: October, 3, 1995

A circuit arrangement is disclosed that performs one or all of the functions selected from the group comprising (1) establishing a threshold level for detecting and encoding selected parameters of RF signals; (2) establishes a threshold level that corresponds to a signal-to-noise ratio (SNR) and which is used for detecting and encoding selected parameters of RF signals; and (3) determining the tangent angle of the received RF signals which is further used for measuring the frequency of the RF signal. The circuit arrangement comprises a microwave correlator including a power divider, a delay line, a quadrature coupler, and two multipliers. The circuit arrangement further comprises an RF amplifier, a bandpass filter, low pass filters, analog-to-digital converters, and preferably a PROM. The microwave correlator splits the RF signals between two paths, with one path being delayed with respect to the other, and then multiplies delayed RF signals with the undelayed RF signals to provide a video signal containing both sine and cosine information. The sine and cosine information are converted to digital representations which are used to provide any of the three features of the present invention.