Magnetic techniques for mechanizing a frequency detection channel at two megacycles

IN A PULSED-doppler coherent-type radar system, the basic target information is relative velocity (range rate). In the air-borne system of interest in this paper, signals received from a moving target are fed from a number of range-gated receivers to a filter bank and interrogator (FBI) unit. Within this unit, target detection decisions for each range-gated receiver are determined by measuring this relative velocity; these measurements are a function of the doppler-shifted frequency of the returned signals. This information is extracted in the FBI in a 2-cycle process: During the first cycle, the signal information from each range-gated receiver is velocity (frequency) quantized in a multichannel bank. Each quantizing channel is termed a frequency detection channel (FDC); the velocity quantized signal within each FDC is detected and stored. Each range-gated receiver and its corresponding FDCs form the elements of a velocity-range-gate matrix. During the second cycle, this matrix is interrogated sequentially to reveal the previously stored information. Suitable processing determines if signals exist above a predetermined threshold level; these detection decisions are generated in binary form and delivered to a data processor.