Raytheon Company

John D Collins

Arthur M Cappon

William A Sciarretta

Jay P Sage

Douglas S MacFall, Jr

A frequency modulated continuous wave radar wherein analog signals received from a target are converted to digital form, processed by correlation with differently delayed signals, also in digital form, of a modulation waveform repetitively applied to the transmitted signals and the frequency spectra of the resulting signals are determined, such spectra being indicative of range of the target. In addition, a digital correlator adapted to perform the desired correlation is shown.

Continuous wave radar with ranging capability

An arrangement is shown to process mainlobe echo signals and range sidelobe signals in the receiver of a pulse compression radar by first converting such signals to a set of digital numbers and then correlating, number by number, such set with a set of reference numbers describing the mainlobe echo signals and the negative of selected range sidelobe signals.

Processing arrangement for pulse compression radar

A signal processor is disclosed wherein an intermediate frequency chirp pulse is pulse compressed and the linearly frequency modulated, intermediate frequency component of such compressed pulse is removed. With such an arrangement, various weighting techniques may be effectively used to reduce sidelobes of the compressed pulse while, in a radar system application, retaining the sense of the frequency of a Doppler shifted compressed pulse.

Signal processor

A signal processor having a plurality of charge transfer devices adapted for coupling to an input signal source. Each one of such devices produces a sample of the input signal in response to a sampling signal. An input shift register having a plurality of serially coupled stages is provided, each one of such stages being coupled to a corresponding one of the charge transfer devices. Circuitry is included for enabling the sampling signal to be sequentially produced at an output of each one of the serially coupled stages, enabling sequential samples of the input signal to be produced in corresponding ones of the charge transfer devices.

A signal processor having a plurality of charge transfer devices fed by a series of input signals, input addressing circuitry for enabling sequential samples of such each one of input signals to be stored in corresponding ones of the charge transfer devices, such charge transfer devices storing corresponding sets of samples, output addressing circuitry for reading, sequentially, the sets of samples, the charge transfer devices, input addressing circuitry and output addressing circuitry being formed on a single crystal substrate.

A signal processor suitable for real time processing of a complex signal having a relatively narrow frequency spectrum is disclosed. Such signal processor includes a so-called delay line time compressor adapted to receive digital signals corresponding to samples of the complex signal into selected stages thereof and to convert such digital signals into a resulting complex signal, analogous to the complex signal being processed, but having a relatively wide frequency spectrum. The signal processor also includes a digitally controlled oscillator in combination with a single side band generator to produce frequency-varying heterodyning signals which, when mixed with the resulting complex signal, permit separation of the frequency components of such resulting signal to permit any further separate processing of each one of such components.

Recirculating delay line time compressor having plural input taps

A frequency spectrum analyzer adapted for use in a real time signal processing radar system is disclosed. In such system a plurality of sets of radar returns, each one of such sets corresponding to radar returns from objects disposed in each one of a like plurality of range cells, is stored in a time compressor section, the radar returns in each one of the sets thereof being stored at the pulse repetition frequency (PRF) of such radar system. After storage of such radar returns, a like plurality of chirp pulses is produced, each one of such pulses having a dispersive time K.tau.. Synchronously with each one of the chirp pulses, one of the plurality of sets of stored radar returns is retrieved from the time compressor section, in a time duration equal to K.tau.. Each one of the retrieved sets of radar returns is mixed with a corresponding one of the plurality of chirp pulses to produce a series of mixed signals which is coupled to a pulse compressor. Each one of the mixed signals is compressed into a pulse occurring at a time related to the Doppler frequency of any object in the range cell producing such associated radar returns. The time compressor section is used prior to pulse compression to effectively 'match' the radar dwell time, generally several milliseconds in duration, to the dispersive time of the chirp pulse, generally several microseconds in duration, thereby enabling the pulse compressor to include a practical surface acoustic wave (SAW) delay line. Further, the 'compressive' bandwidth, .beta., of the pulse compressor is equal to, or greater than, the dispersive bandwidth of the chirp pulses, thereby to maximize the power in the compressed pulses. Means are provided to adjust the dispersive time of the chirp pulse, thereby to correspondingly adjust the effective number of frequency resolution cells of the frequency spectrum analyzer.

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Burlington, MA, United States of America

John D Collins