US3668702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive matched filter for radar signal detector in the presence of colored noise
Assignee: TDK Micronas GmbH
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Filing: 1970-10-30
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Granted: 1972-06-06
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Expires: 1990-10-30
Abstract
Abstract A system for electromagnetic signal detection having an adaptive circuit generating a time-varying matched filter characteristic whereby the statistical properties of additive noise appearing in a receiver output may be ''''tracked.'''' The statistical behavior of ''''colored'''' noise is evaluated and the matched detection filter characteristics are modified accordingly, so that detector performance for signals in ''''colored'''' noise is comparable to that achieved by an optimum invariant matched filter for signal detection in ''''white'''' noise.
Inventors
- 👤 James W Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:54
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/292; G01S7/2921
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
219 words
In a radar equipment including pulsed radar transmitting and receiving means, a system for enhancing the detectability of pulsed received signals in colored noise comprising: sampling means operating at a predetermined repetition rate and sample duration for sampling the received signal and noise to produce a plurality of successive samples comprising a vector y(t); a first whitening filter responsive to said y(t) signals for processing said samples, said first whitening filter comprising a separate channel for each signal component of said vector, said channels each including a plurality of cascaded automatic amplitude control circuits, thereby being adaptive to the statistical characteristics of noise in said y(t) signals; a second whitening filter responsive to second samples characterizing the transmitted waveform shape, said second whitening filter comprising a plural automatic amplitude control means controlled by the corresponding means in said first whitening filter, thereby to slave said second whitening filter to the adaptive characteristics of said first whitening filter; analog multiplying means for individually multiplying the vector components of the output of said first whitening filter by the corresponding vector components of the output of said second whitening filter to produce a whitened product vector signal; and threshold means for detecting useful signals within said whitened product vector signal exceeding the amplitude threshold formed by said second whitening filter output vectors.
Claim 2
Dependent Claim
219 words
In a radar equipment including pulsed radar transmitting and receiving means, a system for enhancing the detectability of pulsed received signals in colored noise comprising: sampling means operating at a predetermined repetition rate and sample duration for sampling the received signal and noise to produce a plurality of successive samples comprising a vector y(t); a first whitening filter responsive to said y(t) signals for processing said samples, said first whitening filter comprising a separate channel for each signal component of said vector, said channels each including a plurality of cascaded automatic amplitude control circuits, thereby being adaptive to the statistical characteristics of noise in said y(t) signals; a second whitening filter responsive to second samples characterizing the transmitted waveform shape, said second whitening filter comprising a plural automatic amplitude control means controlled by the corresponding means in said first whitening filter, thereby to slave said second whitening filter to the adaptive characteristics of said first whitening filter; analog multiplying means for individually multiplying the vector components of the output of said first whitening filter by the corresponding vector components of the output of said second whitening filter to produce a whitened product vector signal; and threshold means for detecting useful signals within said whitened product vector signal exceeding the amplitude threshold formed by said second whitening filter output vectors.
Claim 3
Dependent Claim
56 words
The invention according to claim 1 including squaring means responsive to the vector components of said second whitening filter for generating a corresponding set of squared vector components, said squaring means being connected between said second whitening filter output vectors and said threshold means, whereby said squaring means output becomes the reference for said threshold means.
Claim 4
Dependent Claim
85 words
The invention set forth in claim 2 in which said whitening filters each include a pairwise transformation unit connected to each pair of components in said y(t) vector, said transformation units each having two outputs and being adapted to provide the sum of the signals on said input pair on one of said outputs and the difference of the signals on said input pair at the other of said outputs, said outputs each including one of said cascaded automatic amplitude control circuits in series therewith.
Claim 5
Dependent Claim
75 words
The invention set forth in claim 3 in which said automatic amplitude control circuits include a controllable variable gain element in series with each output of said pairwise adaptive transformation units, and a control loop responsive to the output of said variable gain element to produce and apply a control signal to said variable gain element in a manner so as to regulate the output amplitude of said variable gain element at a predetermined level.
Claim 6
Dependent Claim
61 words
Apparatus according to claim 4 in which said control loop comprises at least a squaring circuit responsive to the output of said variable gain element, an integrator responsive to the output of said squaring circuit and an exponential response circuit to produce said control signal in the form of the natural log of the effective gain of said variable gain element.
Claim 7
Dependent Claim
35 words
Apparatus according To claim 5 in which said control loop includes a predeterminable gain element ahead of said integrator, thereby to provide adjustment of the time constant of response of said automatic amplitude control circuits.
Claim 8
Dependent Claim
57 words
Apparatus according to claim 4 in which the outputs of said pairwise transformation units of said second whitening filters are fed to cascaded automatic amplitude control circuits comprising said controllable variable gain elements, and said variable gain elements are each responsive to said control signals generated in corresponding automatic amplitude control circuits of said first whitening filter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |