US 4,398,196 AGranted

Instantaneous broadband radar signal pulse detector

AssigneeWestinghouse Electric Corp.

InventorRichard J. Wiegand

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Abstract

A pulse detection radar signal receiver is disclosed which includes at least one pulse detection channel that has an RF amplifier and a feedback signal path coupling the output to the input thereof for recirculation of signals therethrough. The feedback path includes a signal-to-noise (S/N) enhancer circuit and an inhibiting means, preferably disposed in series therewith. The S/N enhancer circuit is operative to adaptively focus a narrow enhancement bandwidth about the frequency of an input signal, which has a power level greater than a predetermined threshold level, for enhancing signals which have frequencies within said enhancement bandwidth and for attenuating signals which have frequencies outside said enhancement bandwidth. The enhanced and attenuated signals are provided to the input of the RF amplifier for recirculation therethrough. Thus, after one or more recirculations through the loop, an RF pulse signal, which is substantially at one carrier frequency, may be amplified and the RF noise signals, which are broadband in nature, may be attenuated. Accordingly, a weak RF pulse signal, after a number of recirculations, may become distinguishable from the broadband RF noise signals. When the RF pulse signal is detected, the inhibiting means is operated to squelch the circulated signals, momentarily, from passing through the feedback path.

Claims9

Dependent claims

A radar signal receiver including at least one pulse detection channel operative to process received radar signals having carrier frequencies within a predetermined broadband microwave channel frequency range to detect the presence of a radar pulse, each pulse detection channel comprising:

an RF amplifier having an input and an output and operative to amplify received RF signals;
means for detecting a radar pulse from the amplified RF signals of said RF amplifier and for generating a pulse detection signal in response to said detection;
and an improvement of apparatus for increasing the sensitivity of detection of radar pulses especially in the presence of noise signals distributed within the corresponding broadband channel frequency detection range, said apparatus comprising:
a feedback signal path coupling the output to the input of said RF amplifier;
a signal-to-noise (S/N) enhancer circuit disposed in said feedback signal path and operative to adaptively focus a narrow enhancement bandwidth about the frequency of an input signal, which has a power level greater than a predetermined threshold level, for enhancing signals which have frequencies within said enhancement bandwidth and for attenuating signals which have frequencies outside of said enhancement bandwidth, said enhanced and attenuated signals being recirculated through said RF amplifier utilizing said feedback signal path;
and
means, disposed in said feedback signal path, for inhibiting, at times, the recirculation of said signals through said feedback signal path as governed by said pulse detection signal.

4 more elements

an RF amplifier having an input and an output and operative to amplify received RF signals;
means for detecting a radar pulse from the amplified RF signals of said RF amplifier and for generating a pulse detection signal in response to said detection;
and an improvement of apparatus for increasing the sensitivity of detection of radar pulses especially in the presence of noise signals distributed within the corresponding broadband channel frequency detection range, said apparatus comprising:
a feedback signal path coupling the output to the input of said RF amplifier;
a signal-to-noise (S/N) enhancer circuit disposed in said feedback path including:
means for separating the coupled output signal of said RF amplifier into signal portions corresponding to a plurality of preselected frequency bandwidths which cover the broadband microwave channel frequency range;
a S/N enhancer for each separated signal portion, each enhancer operative to adaptively focus a narrow enhancement bandwidth about the frequency of an input signal, which has a power level greater than a predetermined threshold level, for enhancing signals which have frequencies within said enhancement bandwidth and for attenuating signals outside of said enhancement bandwidth;
and
means for combining the enhanced and attenuated signals of said plurality of signal portions to form a combined signal for recirculation through said RF amplifier;
and
means, disposed in said feedback path, for inhibiting, at times, the recirculation of said combined signal through said feedback path as governed by said pulse detection signal.

8 more elements

Dependencies are inferred from the claim text.