Automatic thresholding and reference circuit
AssigneeThe United States of America as represented by the Navy
InventorRichard M. Smith
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Abstract
An automatic thresholding reference and detection circuit which generates a signal in time which is a replica of the radar return signal's doppler spectrum. The radar signal return is processed by a target signal channel having a narrow bandwidth filter which produces a fine resolution replica of the signal spectrum, and by a reference signal channel having a wider bandwidth filter, which produces a smeared (or average) replica of the signal spectrum. The output of the reference signal channel is a threshold signal which, when compared to the output of the target signal channel, allows only the target signals to be passed for further processing and rejects clutter and thermal noise.
Claims9
An automatic, adaptive-threshold circuit for processing signals received from a pulse Doppler radar comprising:
- reception means for receiving a radar return signal from said pulse Doppler radar;
- a target channel connected to the output of said reception means, tuned to a first narrow bandwidth, and outputting a first time replica spectrum of said received output from said reception means;
- a reference channel connected to the output of said reception means and in parallel with said target channel, said reference channel tuned to a second narrow bandwidth wider than said first narrow bandwidth and outputting a second time replica spectrum of said received output from said reception means, said second time replica spectrum being coarser than said first time replica spectrum;
- and
- a comparator having a plurality of inputs connected to and receiving the outputs of said target channel and said reference channel, whereby said received radar return signal is processed in parallel fashion by said target and said reference channels, said reference channel output being the automatic, adaptive threshold against which said target channel output is compared in said comparator.
Dependencies are inferred from the claim text.