Abstract: A radar sensor having a signal generating device which generates an outgoing signal as a radar signal that is to be emitted. The radar sensor also has a signal receiving device for receiving and processing received signals as reflected radar signals. The received signals can be processed with a prediction method in order to determine a predicted signal, which can be compared to the received signal in order to eliminate disruptions deviating therefrom.

Abstract: A computer-implemented method of identifying a target includes receiving at least one data input related to the target from at least one data source. At least one acoustic parameter is calculated from the at least one data input. A target identification algorithm is applied to at least one acoustic data parameter. An identification of the target is produced from at least one acoustic parameter when the target identification algorithm is applied thereto. The identification of the target is displayed.

Abstract: In a general aspect, a method for transmitting data by inductive coupling can include applying, at a rate of a data-carrying signal, a plurality of bursts of a periodic signal to a tuned inductive antenna circuit. The method can also include producing, in the tuned inductive antenna circuit, an antenna signal. The antenna signal can generate a magnetic field. The method can further include delimiting an amplitude of each burst of the plurality of bursts of the periodic signal in accordance with an envelope signal having a rising edge and a falling edge. The delimiting the amplitude of each burst of the plurality of bursts of the periodic signal can include generating the plurality of bursts of the periodic signal using a set of points. The set of points can define, by discrete values, a burst of the plurality of bursts of the periodic signal.

Abstract: A distance measuring sensor (10) for a detection and distance determination of objects (18) in a monitoring area, the sensor (10) having a transmitter (12) for transmitting transmission pulses, a receiver (20) for generating a reception signal from transmission pulses remitted from the monitoring area, an A/D converter (38) for digitizing the reception signal, and a control and evaluation unit (28, 30), which is configured to transmit a plurality of transmission pulses via the transmitter (12), to accumulate the respective reception signals generated by the receiver (20) in a histogram (110), and to determine, from the histogram (110), a reception point in time and thus a measurement value for the signal time of flight from the sensor (10) to the object (18), wherein the sensor (10) comprises a noise generator (40) configured to add a noise signal to the reception signal prior to its digitization in the A/D converter (38).

Abstract: An apparatus configured to apply equalization to an input data signal and detect data based on the equalized data signal. The apparatus includes a passive equalizer comprising a first signal path configured to generate a first signal based on an input signal, and a second signal path configured to generate a second signal by filtering the input signal. The apparatus further includes a sense amplifier having an input circuit configured to generate a third signal related to a combination of the first and second signals, and a data detection circuit configured to generate data based on the third signal. The data detection circuit may be configured as a strong-arm latch. The third signal may be a differential current signal including positive and negative current components. The strong-arm latch generating data based on whether the positive current component is greater than the negative current component.

Abstract: A method for detecting the position of a piston of a piston cylinder is provided. A microwave transmit signal is emitted in the direction of the piston and microwaves reflected from the piston are detected. The transmit signal is a modulated signal with a base frequency sinusoidally modulated at a modulation frequency. An evaluation of the phase between transmit signals and receive signals is performed. A phase determination at the baseband and a simultaneous phase determination at at least one sideband are also performed. The phase determination at the baseband is used for fine determination of the piston position and the phase determination at the at least one sideband is used for coarse determination of the piston position. Bandpass filtering on receive signals and evaluation transmit signals is performed with respect to the base frequency or an intermediate frequency. Bandpass filtering is performed with respect to the modulation frequency.

Abstract: A radar device capable of removing noise signals before digital conversion and detecting an object with high precision by a simple configuration is provided. In a transmitting RF unit 110, a signal switch 141 is switched so that the noise signal generated by the operation of a first switch 111 passes through a signal delaying device 142. The signal switch 141 is switched so that the noise signal generated by the operation of a second switch 112 passes through a signal delaying device 143. Furthermore, the signal switch 141 is switched so that a baseband pulse signal obtained when the first switch 111 and the second switch 112 are operated at the same time passes through a signal delaying device 144. In a signal synthesizer 145, synthesizing is carried out so that the noise signals mixed in pulse signals are cancelled out.

Abstract: Signal compensation systems and methods compensate an estimated range profile from a plurality of detected signal returns from a true range profile, wherein the signal returns correspond to an emitted stepped frequency pulse-train. An exemplary embodiment utilizes knowledge of the radar system design to identify locations, predict power levels, and suppress the contributions of stepped-frequency range sidelobes (ambiguous peaks) in the estimated range profile, resulting in a cleaner and more accurate radar display.

Abstract: A transmitter apparatus generates a RF pulse signal having alternating high-amplitude pulse-on intervals and low-amplitude pulse-off intervals, and supplies the RF pulse signal as respective individual transmission signals of antenna elements of an array antenna, with the individual transmission signals having a phase distribution during each pulse-on interval whereby a beam is transmitted from the antenna in a predetermined transmission direction. During each pulse-off interval, a different phase distribution is established for the individual transmission signals, thereby reducing the level of noise radiated in the transmission direction during each pulse-off interval.

Abstract: Marine radar systems and methods for producing low power, high resolution range profile estimates. Non-linear Frequency Modulation (NLFM) pulse compression pulses are frequency stepped to form a low power, wide-bandwidth waveform. Periodically, calibration filters are determined and applied to return signals for correcting non-ideal effects in the radar transmitter and receiver.

Abstract: It is possible to generate D/A conversion voltage in which an error generated by numeric irregularities of a D/A conversion element such as resistor constituting a D/A converter 11 is corrected. A waveform generation method characterized in that input data into a D/A converter 11 are provided to the D/A converter in order at a timing at which a voltage of a desired waveform which has D/A conversion data indicating a conversion amount of the input data obtained by varying the input data by a minimum conversion unit or a unit obtained by multiplying the minimum conversion unit by an integer, and which varies with time series, becomes substantially equal to a D/A-converted voltage, whereby the D/A-converted voltage is generated in accordance with the desired waveform.

Abstract: One embodiment relates to a transceiver. The transceiver includes first and second phase-locked loops. The first phase-locked loop is adapted to receive a reference signal and output a transmission signal based on the reference signal. The second phase-locked loop is adapted to receive the reference signal and output a local oscillator (LO) signal based on the reference signal. The frequency of the LO signal is shifted relative to the frequency of the transmission signal. Other methods and systems are also disclosed.

Abstract: A filter scheme for broadcast interference cancellation that is computationally efficient and numerically robust Airborne Low Frequency Synthetic Aperture Radar (SAR) operating in the VHF and UHF bands has been shown. At least interference Doppler filtering or interference cancellation is utilized. The interference cancellation involves prediction of the interference for each particular reception interval of mixed interference and radar ground response. This prediction is then coherently subtracted from the incoming signal.

Abstract: It is possible to generate D/A conversion voltage in which an error generated by numeric irregularities of a D/A conversion element such as resistor constituting a D/A converter 11 is corrected. A waveform generation method characterized in that input data into a D/A converter 11 are provided to the D/A converter in order at a timing at which a voltage of a desired waveform which has D/A conversion data indicating a conversion amount of the input data obtained by varying the input data by a minimum conversion unit or a unit obtained by multiplying the minimum conversion unit by an integer, and which varies with time series, becomes substantially equal to a D/A-converted voltage, whereby the D/A-converted voltage is generated in accordance with the desired waveform.

Abstract: A radar apparatus includes a PN code generator for generating a PN code, a variable delay device for delaying the PN code, an oscillator for generating a high-frequency signal, a transmission frequency multiplier for multiplying a frequency of a transmission differential signal obtained by being divided from the high-frequency signal by 3, a reception frequency multiplier for multiplying a frequency of a reception differential signal obtained by being divided from the high-frequency by 3, a transmitter for generating a radar wave by using the differential signal obtained through the multiplication by the transmission frequency multiplier and the PN code generated by the PN code generator, and a receiver for generating an in-phase signal and a quadrature signal from a reflected wave by using the differential signal obtained through the multiplication by the reception frequency multiplier and the PN code delayed by the delay device.

Abstract: An FET amplifier includes an FET for amplifying a high-frequency signal to be input to the gate on the basis of a gate bias voltage from a gate bias control circuit. In the FET amplifier, a high-frequency signal input circuit and the output portion of an inverting amplifier are made conductive to the gate of the FET. A voltage stabilizing circuit generating a positive DC constant-voltage signal is made conductive to the non-inverting input portion of the inverting amplifier, and a gate bias control signal input circuit is made conductive to the inverting input portion through an inverter circuit. When the output voltage from the inverter circuit is 0 V, the inverting amplifier outputs a positive gate bias voltage (in the High state) and, when the output voltage from the inverter circuit is a fixed positive voltage, the inverting amplifier outputs a negative gate bias voltage (in the Low state) lower than the pinch-off voltage of the FET.

Abstract: The present invention is directed to an integrated circuit device that includes a primary signal synthesizer configured to generate a free-running first digital frequency signal and at least one secondary signal synthesizer disposed in parallel with the primary signal synthesizer and configured to generate a free-running at least one second digital frequency signal. A switch element includes a first switch input coupled to the primary signal synthesizer and at least one second switch input coupled to the at least one secondary signal synthesizer. The switch element is configured to select a switch output that provides either the free-running first digital frequency signal or the free-running at least one second digital frequency signal based on a switch control input.

Abstract: In a radar sensor, a continuous microwave signal is passed through an RF switch which is periodically controlled by a pulse signal. The pulse signal is frequency modulated in such a way that the spectrum of the pulse signal is expanded without decorrelation occurring. Using this arrangement, the noise level is kept low and the detection range is increased.

Abstract: A method for enlarging the interference-free dynamic range of non-linear signal-processing components in receiver systems, in the conversion of input frequencies fin into output frequencies fout. According to the invention, at least one linear combination of at least one input frequency fin,t, fin,b and a fixed, predetermined oscillator fLOn of the components is calculated from the output signal of the component, for at least one output frequency fout,s, fout1,s, fouts,2, which combination is compared with any desired output frequency fout,t of the component, whereby the output frequency fout,s, fout1,s, fouts,2 is then recognized as a spur and eliminated from the output signal of the component, if the calculated linear combination corresponds to any desired output frequency fout,t of the component, within a frequency and power range that can be predetermined.

Abstract: Apparatus for producing an amplified Radio Frequency pulse includes a controller for monitoring the output amplified pulse and determining therefrom a correction for a deviation in the characteristics. The correction is applied by a phase shifter or amplitude controller for subsequent pulses. The apparatus is particularly applicable to pulses used by RADAR equipment and allows the use of longer duration pulses. This improves the detection range of the equipment.

Abstract: A conventional waveform generation circuit was required to increase a number of bits or a sampling rate for a D/A converter to enhance a precision of waveform shaping, and had a problem that a cost was increased. Therefore, as a method for enhancing the precision of waveform shaping, a quantization error of an output waveform is made smaller by controlling an output time interval of an output value from a D/A converter so as to make a difference in an output voltage between target waveform and output waveform smaller. As a result, even if the D/A converter has a small number of bits, the waveform can be generated at high precision. Also, this waveform generation method may be applied to modulation control of a radar apparatus, as a result, constituting a small and inexpensive modulation circuit for an oscillator.

Abstract: A radar device is described having an arrangement to generate a carrier signal having a carrier frequency fT, an arrangement to generate pulses having a pulse repetition rate fPW, an arrangement to split the carrier signal between a transmission branch and a reception branch, an arrangement to delay the pulses, an arrangement to mix the carrier signal in the reception branch with a reception signal, and an arrangement to integrate the mixed signal. An arrangement to modulate the carrier signal in the transmission branch with the delayed pulses and an arrangement to alter the delay in the pulses according to a predetermined code are also provided. A method of suppressing interference with the functioning of a radar device is also described.

Abstract: A system and corresponding method for the concurrent operation of multiple radar systems on a common frequency and in the same geographical area includes a waveform generator that specifies certain operating parameters for the transmitted radar pulses. In a first instance, the carrier frequency can include an offset for each radar system. In a second instance, complementary codes can be used for the radar pulses such that each radar system operates with a unique code for substantially reducing the cross-talk between the radar systems. In another instance, both carrier frequency offset and complementary coded waveforms can be used to increase the number of radar systems that operate concurrently. Carrier frequency offset can also be used to combat range-wrap by using different carrier frequencies for adjacent radar pulses.

Abstract: A current source modulator (202; 302, 502) provides power to radar transmitters. The modulator comprises a power supply (210, 310, 510) providing, when enabled, a known current to a storage capacitor (145). A comparator circuit (220) provides a signal (V220) when voltage (VC) across the storage capacitor (145) falls a reference voltage, and an enable circuit (225) responds to the comparator signal (V220) and an ON command signal to enable the power supply (210, 310, 510). The modulator (202, 302, 502) further includes a network (220N) associated with the comparator circuit (220) to retain the value of the signal (provide hysteresis) when the voltage across the storage capacitor is above the reference voltage. The modulator (202, 302, 502) may include a second network (320N) associated with a second comparator circuit, operable to retain a second signal when capacitor (145) voltage VC is above a reference voltage. In this aspect, there is a rapid charge and a trickle charge that reduces any charging overshoot.

Abstract: A wave-form generator drives a number of microwave generating devices each operating at different frequency bands. The output of each microwave generator is connected to its own transmission channel of limited bandwidth which contains all the non-linear components necessary for transmission such as an amplifier, T/R switch, rotary joint and beam switch. These individual channels are finally combined onto a common wideband channel which contains only substantially linear components such as a single waveguide and the antenna itself. Because of the isolation between channels there is little or no opportunity for the generation of harmonics or intermodulation distortions which would otherwise occur in a transmitter capable of operating over a very wide bandwidth.

Abstract: A method for enlarging the interference-free dynamic range of non-linear signal-processing components in receiver systems, in the conversion of input frequencies fin into output frequencies fout. According to the invention, at least one linear combination of at least one input frequency fin,t, fin,b and a fixed, predetermined oscillator fLOn of the components is calculated from the output signal of the component, for at least one output frequency fout,s, fout1,s, fouts,2, which combination is compared with any desired output frequency fout,t of the component, whereby the output frequency fout,s, fout1,s, fouts,2 is then recognized as a spur and eliminated from the output signal of the component, if the calculated linear combination corresponds to any desired output frequency fout,t of the component, within a frequency and power range that can be predetermined.

Abstract: A radar device includes elements for generating a carrier signal having a carrier frequency fT, elements for generating pulses with a pulse repetition frequency fPW, elements for distributing the carrier signal to a transmission branch and a receiving branch, elements for modulate the carrier signal in the transmission path using the undelayed pulses, elements for modulating the carrier signal in the receiving branch using the delayed pulses and for generating a reference signal, elements for mixing the reference signal in the receiving branch with a received signal and elements for integrating the mixed signal. Elements are provided for binary phase shift keying (BPSK) modulation of the carrier signal and elements are provided for switching the polarity of the received signal. A method for suppressing interference in a radar device is also described.

Abstract: A method for transmitting a radar signal comprises the step of transmitting a series of pulses, each of the pulses being separated in time by an interpulse period, and each of the pulses in the series being modulated in accordance with a different character of a first code

Abstract: An apparatus and method of dynamically optimizing an acquisition range of a radar system, including modulating a CW radar signal with a PN code that has an adjustable code frequency of modulation and an adjustable chip length. The method includes transmitting the modulated radar signal and receiving a return radar signal, based on the transmitted radar signal. The method continuously measures a SNR of the received return radar signal, and adaptively tunes the adjustable code frequency of modulation, and adaptively tunes the adjustable chip length, based on the continuously measured SNR. In this manner, the acquisition range of the radar system is optimized.

Abstract: The present invention relates to a light-wave rangefinder using a pulse method, which can reduce a measurement error, in which a tuned amplifier converts an electric signal of a light receiving unit into a damped oscillation waveform and thereby an arithmetic processing means can calculate a distance from a measuring position to a reflecting object on the basis of the damped oscillation waveform of the tuned amplifier. An optical noise sampling unit samples an optical noise produced in the rangefinder; an optical-noise storage unit stores sampling data of the optical-noise sampling unit; an arithmetic processing means reduces a measurement error caused by an optical noise on the basis of the sampling data of the optical-noise storage unit; and thereby a distance, a measurement error of which is reduced, can be calculated.

Abstract: A power regulator regulates the power provided to a transistor-based circuit, such as that which might be employed in a high stability MTI radar system. According to the invention, a variable reference voltage is controlled based on the frequency of operation. The output voltage of the power regulator is then modified accordingly. Preferably, the reference voltage is controlled based on the location of the target frequency in relation to the overall operational frequency band, which has been divided into a series of sub-bands.

Abstract: A radar device is described having means (12) for generating a first code, means (18) for modulating a transmission signal in a transmitting branch using the first code, means (32) for delaying the first code, means (20) for modulating a signal in a receiving branch using the delayed first code, and means for mixing a reference signal with a reception signal, multiple receiving channels (111, 112, . . . 11k) being provided, the receiving channels (111, 112, . . . 11k) having means (1201, 1202, . . . 120k) for generating additional codes (C1, C2, . . . Ck), the receiving channels (111, 112, . . . 11k) having means (131, 132, . . . 13k) for demodulating using the respective additional codes (C1, C2, . . . Ck), and means (15) being provided for modulating the transmission signal using at least one of the additional codes (C1, C2, . . . Ck). A method which may be implemented advantageously using the radar device described is also described.

Abstract: Process and device for reducing the spectral line noise inside an aircraft, especially a rotating-wing aircraft, in particular a helicopter. Said device (1) comprises sensors (Ca, Cb) for measuring the values of vibratory and/or acoustic parameters, controllable mechanical elements (A) forming secondary sources of noise, and a main computer (CAL) determining, on the basis of the values measured by the sensors (Ca, Cb), control commands for the mechanical elements (A), as well as at least one reference sensor (CO) for measuring a reference parameter which is correlated with the noise, and possibly an auxiliary computer (4) for calculating, on the basis of the values measured by the reference sensor (CO), a reference signal, and said main computer (CAL) determines the control commands by carrying out filtering with respect to the reference signal.

Abstract: A multifrequency phase-coded signal structure is presented for use in a system like a radar or sonar or detecting a remote target. The signal structure comprises at least one pulse signal in the form of a mutually complementary set of M sequences, each sequence being composed of M phase-modulated bits. Each two adjacent sequences are modulated on subcarriers separated by a frequency fs such that fs=1/tb, tb being a bit duration, and a the subcarriers are transmitted simultaneously.

Abstract: The invention relates to solid-state radar transmitter, comprising a number of amplifier modules (4.i). To prevent the trailing edge of a steer pulse supplied to the radar transmitter from becoming too steep when passing the amplifier modules (4.i) driven in saturation, the supply voltage on at least One amplifier state in each amplifier module (4.i) is switched off just before the end of the steer pulse.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a “zero” value and a “cal” value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: A radar exciter including a direct digital synthesis (DDS) wideband waveform generator which performs the frequency synthesis function heretofore performed by a direct analog synthesizer. This is achieved by deriving the DDS frequencies, the exciter RF frequencies, the radar synchronizer clock frequency and receiver analog/digital (A/D) converter clock frequency from a common signal source generating a master frequency. The present invention eliminates the direct analog synthesizer and relies solely on the digital generation of waveforms by a DDS wideband waveform generator which performs a discrete sampling process so as to provide coherent frequency and timing relationships.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: A procedure and a system increase the performance of a group of radar units. The radar units are arbitrarily located in such a way that the respective antenna beam of a radar unit functioning as a normal radar at least partially coincides with the antenna beam of at least one other radar unit in the group. The radar units are synchronised to transmit alternately and in turn, preferably with an increased energy output. All the radar units in the system are synchronised to work continuously in their ordinary reception mode. In this way at each moment echo signals originating from the radar unit transmitting at that moment are received and processed.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: A method and apparatus for preventing the occurrence of range ambiguities and Doppler ambiguities in both a radar and sonar environment. A series of N pulses are produced, each of which contains a number of contagious subpulses. Each of the subpulses exhibit a different frequency than the remaining subpulses in that particular pulse. Furthermore, the order of appearance of the subpulses in each of the pulses is unique with respect to the remaining pulses in the series. A matched filter receiver and Doppler processor are used to provide auto correlations and cross correlations to prevent the range ambiguities and Doppler ambiguities.

Abstract: For less expensive estimation the impulse response x.sub.MOS of a high-resolution, band-limited radar channel in a radar station operating with an expanded transmitted pulse a(t), from a received signal e, over which a correlated or uncorrelated additive interference signal n can be superimposed, with the use of knowledge about the spread code c and the use of a channel estimator with which a so-called linear, optimum unbiased estimation of the radar channel impulse response x.sub.MOS is performed in a time range covering M range gates of interest, the linear, optimum estimation in the unbiased channel estimator is modified in such a way that the pulse response x.sub.MOS of the band-limited radar channel is determined according to the basic principle of a multiplication of the sampled received signal e and an inverse estimation matrix A.sub.E.sup.-1. The matrix A.sub.E is formed by the extension of the rectangular matrix represented by the components c.sub.

Abstract: A radar apparatus provided with a transmitting unit, antenna unit and a receiver unit. The transmitting unit transmits pulses having a modulation for enabling pulse compression on reception. As an ECCM feature, the radar apparatus is further provided with a blanking circuit. The blanking circuit includes two filters, one filter being responsive to the first half of the transmitting pulse only and the other filter being responsive to the second half of the transmitting pulse only. Blanking occurs if both filters simultaneously produce an output.

Abstract: A system (10) for reducing range sidelobes adapted for use with pulsed radar systems. The inventive system (10) includes a mismatched filter (90) for correlating a received signal (84) with a correlator signal (92) having a different length than the transmit signal (84) and for providing a predetermined number of reduced range sidelobes (97) at the output of the mismatched filter (90). The mismatched filter (90) has a first locally optimum sequence that is the correlator signal (92). The mismatched filter (90) has an input device (86) for receiving an extended locally optimum sequence (84) that is a received signal (84). The first locally optimum sequence (92) is a sub-sequence of the extended locally optimum sequence (84). In a specific embodiment the mismatched filter (90) has a Barker-based code that is the correlator signal (92). The mismatched filter (90) has an input device (86) for receiving an extended Barker-based code that is a received signal (84).

Abstract: An apparatus and method of linear frequency modulation waveform bandwidth multiplication including a digital linear frequency modulation waveform synthesizer for generating a synthesized waveform having an upchirp component of linearly varying frequency during a first half signal duration of the synthesized waveform followed by a downchirp component having linearly varying frequency during a second half of the signal duration of the synthesized waveform. The synthesized waveform is upconverted and subsequently bandpass filtered to provide a filtered waveform to a mixer for mixing with local oscillation signals. The upchirp and downchirp components of the filtered waveform are respectively mixed by first and second local oscillation signals having respective first and second oscillation frequencies in the mixer.

Abstract: In a method to resolve ambiguities in a phase measurement for application in radar interferometry, a frequency estimation method is used, starting from conjugate complex products of pairs of adjacent pixels in an interferogram. The resolution of these products is subsequently reduced through successive addition or averaging, after which the differential phase of adjacent resolution levels is determined in each resolution level. The sum of the phase differences yields the estimated value for the phase gradient which is then used in a known method, such as the least-squares method, to reconstruct the absolute phase, thus resolving the phase ambiguities. The method according to the invention serves to resolve phase ambiguities in radar interferograms without producing the known distortions produced by the existing methods. The method is also robust at low coherence values as they occur in repeat-pass interferometry where the existing methods fail.

Abstract: This invention relates to a method and apparatus for controlling a biphase modulator (602, 702) to improve autocorrelation in pseudorandom noise coded systems. The biphase modulator modulates a carrier frequency with one of two phase states responsive to a pseudorandom noise (PN) binary code sequence. The spectrum (610, 710) at the output of the biphase modulator comprises a plurality of spectral lines separated by the code repetition frequency, including a center spectral line (611, 711) and at least one adjacent spectral line (612-615, 712-717). The magnitude of the center spectral line is measured and compared to a reference to produce a control signal which is responsive to the magnitude of the center spectral line. This control signal is supplied to the biphase modulator for maintaining a predetermined magnitude of the center spectral line thereby achieving a desired spectrum output and improving autocorrelation of the system.

Abstract: A pseudorandom noise coded system (100) compensates for imperfections, improving out of range rejection, and includes a digital correlator (200) having a first complex multiplier (202) receiving a sequence of sampled data words and a sequence of precomputed complex data words and producing a sequence of first complex product words. A second complex multiplier (204) receives the sequence of first complex product words and a precomputed constant word and produces a sequence of second complex product words. A complex multiplexer (206) receives a sequence of binary code states, and the sequences of first and second complex product words and produces a sequence of complex multiplexer output words formed as a replica of either the first or the second complex product words, depending on the binary code. A complex accumulator (208) receives the sequence of complex multiplexer output words and produces a complex accumulated sum word formed as a complex sum of the complex multiplexer output words.

Abstract: This invention improves the detection performance of doppler radar by censoring clutter at the output of the doppler processor, and it functions in operative association with a range CFAR. By a selective rejection of signals based on doppler characteristics and on signal amplitude, it will reduce the sum of clutter and noise at the input to the CFAR. Thus the CFAR detection threshold level is lowered, which thereby improves the detection performance for moving targets.

Abstract: An automatic noise threshold circuit and method automatically sets an operating threshold for a signal receiving section of a laser pulse transmitting device such that a constant noise pulse firing rate is output from a detector to provide maximum return signal sensitivity and enable detection of the weakest possible laser pulse in order to obtain maximum performance out of a laser range finder. The circuit sets the noise pulse rate at that point at which, in conjunction with a firmware based process, the actual return signals from the target can be discrimintated from the accompanying noise.