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US4739331A Expired / Lapsed US ⏱️ 0.0 years remaining

Channelized receiver continuous wave radar system

Assignee: Westinghouse Electric Corp
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Filing: 1985-10-09
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Granted: 1988-04-19
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Expires: 2005-10-09
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Abstract

Abstract A continuous wave radar system arrangement for improving the dynamic range of the radar receiver. The transmitted carrier signal is frequency modulated by a periodic sawtooth waveform causing a predetermined peak frequency shift. The radar receiver includes a plurality of separate receiving channels each selective to a small portion of the transmitted bandwidth. As the sawtooth modulation causes the carrier signal to sweep in frequency, the received leakage and clutter signals in the selective receiving channels are blocked momentarily and individually in each channel. The outputs of the separate receiving channels are combined to form a composite signal of the echo returns. Gaussian filters with quadratic phase compensation are used to provide the selectivity of the receiving channels.

Inventors

  • 👤 Peter H. Pincoffs
  • 👤 Raymond G. Martin

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-06 04:19
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/34; G01S13/343; G01S7/00; G01S7/02; G01S7/35

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 152 words
A radar system comprising: means for transmitting a continuous wave carrier frequency signal; means for modulating the transmitted carrier frequency signal with a sawtooth modulating waveform having sweep and flyback portions; means for capturing echo and clutter signals resulting from the transmitted signal; a plurality of receiving channels each being responsive to only a portion of the bandwidth of the transmitted signal; means for applying the captured signals and transmitter leakage signals to said plurality of receiving channels, said applying means preserving the frequency swing characteristics of said captured and leakage signals; means for attenuating the signals in said receiving channels when the frequency of the transmitted signal is substantially equal to the frequency at which the receiving channel is responsive; and means for combining the signals processed by said plurality of receiving channels to form a composite signal representative of the echoes returned over the complete bandwidth of the transmitted signal.
Claim 2
Dependent Claim 152 words
A radar system comprising: means for transmitting a continuous wave carrier frequency signal; means for modulating the transmitted carrier frequency signal with a sawtooth modulating waveform having sweep and flyback portions; means for capturing echo and clutter signals resulting from the transmitted signal; a plurality of receiving channels each being responsive to only a portion of the bandwidth of the transmitted signal; means for applying the captured signals and transmitter leakage signals to said plurality of receiving channels, said applying means preserving the frequency swing characteristics of said captured and leakage signals; means for attenuating the signals in said receiving channels when the frequency of the transmitted signal is substantially equal to the frequency at which the receiving channel is responsive; and means for combining the signals processed by said plurality of receiving channels to form a composite signal representative of the echoes returned over the complete bandwidth of the transmitted signal.
Claim 3
Dependent Claim 24 words
The radar system of claim 1 wherein each separate receiving channel includes an analog-to-digital converter in the signal processing path after the attenuating means.
Claim 4
Dependent Claim 24 words
The radar system of claim 1 wherein the means for applying the captured signals to the receiving channels includes a plurality of signal mixers.
Claim 5
Dependent Claim 22 words
The radar system of claim 3 wherein each of said mixers is injected by a local oscillator signal of a different frequency.
Claim 6
Dependent Claim 29 words
The radar system of claim 1 wherein the selectivity of said receiving channels with respect to the overall transmitted bandwidth is determined by gaussian filtered with gaussian response characteristics.
Claim 7
Dependent Claim 17 words
The radar system of claim 5 wherein the gaussian filters have response characteristics with quadratic phase compensation.
Claim 8
Dependent Claim 26 words
The radar system of claim 1 wherein the entire flyback transition of said sawtooth modulating waveform generates substantially 180° of phase shift of the carrier signal.
Claim 9
Dependent Claim 23 words
The radar system of claim 1 wherein the sawtooth modulating waveform is modified by the application of amplitude modulation to the sawtooth waveform.
Claim 10
Dependent Claim 18 words
The radar system of claim 1 wherein the combining means includes means for using Fourier transform processing techniques.
Claim 11
Dependent Claim 188 words
A radar system comprising: means for transmitting a continuous wave carrier frequency signal; means for frequency modulating the transmitted carrier frequency signal with a sawtooth modulating waveform having sweep and flyback portions; means for capturing echo and clutter signals resulting from the transmitted signal; a plurality of receiving channels each containing a gaussian filter with gaussian response characteristics and an analog-to-digital converter; means for mixing the captured signals and applying the resulting signals to said receiving channels, with the injection frequencies of said mixing means and the frequency of the passband of said gaussian filters being selected to make said separate receiving channels responsive to only a portion of the bandwidth of the transmitted signal, and with said gaussian filters having response characteristics with quadratic phase compensation; means for attenuating the signals in a specific receiving channel when the frequency of the transmitted signal is substantially equal to the frequency at which the receiving channel is responsive; and means for combining the signals processed by said plurality of receiving channels to form a composite signal representative of the echoes returned over the complete bandwidth of the transmitted signal.
Claim 12
Dependent Claim 188 words
A radar system comprising: means for transmitting a continuous wave carrier frequency signal; means for frequency modulating the transmitted carrier frequency signal with a sawtooth modulating waveform having sweep and flyback portions; means for capturing echo and clutter signals resulting from the transmitted signal; a plurality of receiving channels each containing a gaussian filter with gaussian response characteristics and an analog-to-digital converter; means for mixing the captured signals and applying the resulting signals to said receiving channels, with the injection frequencies of said mixing means and the frequency of the passband of said gaussian filters being selected to make said separate receiving channels responsive to only a portion of the bandwidth of the transmitted signal, and with said gaussian filters having response characteristics with quadratic phase compensation; means for attenuating the signals in a specific receiving channel when the frequency of the transmitted signal is substantially equal to the frequency at which the receiving channel is responsive; and means for combining the signals processed by said plurality of receiving channels to form a composite signal representative of the echoes returned over the complete bandwidth of the transmitted signal.
Claim 13
Dependent Claim 26 words
The radar system of claim 10 wherein the entire flyback portion of said sawtooth modulating waveform generates substantially 180° of phase shift of the carrier signal.

References Cited (Backward Citations)

US3188637A Cited
US3981012A Cited
US3212087A Cited
US3278936A Cited
US3344426A Cited
US4122452A Cited
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US4176351A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-04-19 1991-10-19 1992-04-19 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-04-19 1995-10-19 1996-04-19 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-04-19 1999-10-19 2000-04-19 $7700.00 Window Closed / Lapsed

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