Abstract: A radar system including an azimuthally scanned radar wherein the radar receives echo signals during each of a succession of azimuthally scanned directions of the radar receiving beam. Sequences of samples of data of received echo signals are stored with sets of samples relating to a common range being utilized for developing weighting factors for weighting received echo signals as a function of range. Thereby, dynamic fluctuations in signals strength because of clutter are reduced.

Abstract: A system for transmitting a signal through a reverberant environment characterized by multipath communication which causes dispersion and fading of the signal. The signal is phase modulated onto a carrier which is also modulated by a repeating series of digital pseudo noise code words. The length of each word is equal to the length of a symbol of the signal and synchronized thereto, individual symbols being of shorter duration than the signal fading time. A receiver views symbols via a selector switch which serves as a window for successively viewing portions of substantially identical reverberation patterns of each symbol. A set of matched filters coupled to the selector switch sequentially demodulates the code words to provide a repeating sequence of pulses of amplitude modulated carrier these amplitude modulated pulses having symbol data thereon and being applied to a delay locked loop for the generation of a reference signal for recovering the symbols.

Abstract: A system for forming a beam of radiant energy which is incident upon or radiated from an array of radiating elements such as sonar transducers. As a wavefront progresses across the array, samples of signals received by individual ones of the transducers are selected in accordance with specific beams to be formed, the selected samples being summed together through a sequence of partial summations until a complete summation of a sample of a beam is obtained. The sequence of partial summations is initiated successively for each output sampling interval. For a long array, wherein the transit time of a wavefront across the array is longer than the intersample interval, a plurality of the sequences are generated concurrently. All partial sums for all beam samples are generated periodically at the output sampling rate and are stored in a memory.

Abstract: A communication system for inphase and quadrature modulation of low frequency signals wherein the modulated signal frequency bands lie close to a carrier, the system including a pilot tone having a fixed frequency ratio to the carrier, the system further including a demodulator employing the pilot tone in a phase locked loop for synthesizing a coarse replica of the carrier, a filter incorporating inphase and quadrature channels utilizing the coarse carrier for extracting the actual carrier from the modulated signal spectrum and synchronous detection of the signals by means of the extracted carrier.

Abstract: An organic carbon analyzer system particularly adapted for the continuous analysis of raw sewage of a municipality. A gaseous transport is provided for carrying acidified liquid sewage including dispersed particulate matter through an elongated aeration chamber wherein carbon dioxide evolved from inorganic salts diffuses away from the sewage and into the gas. A second gaseous transport free of carbon dioxide and including an oxidizing agent then carries the sewage into a heated chamber having a tortuous interior surface which provides sufficient retention time to oxidize organic carbonaceous materials of the sewage resulting in a second evolution of carbon dioxide. An analyzer provides a continuous reading of the concentration of the carbon dioxide produced in the heated chamber.

Abstract: A system for portraying data obtained by a radiographic camera, such as an Anger camera, which signals the occurrences of radioactive events and the addresses of locations of the events. Data is obtained from a reference subject and a living subject. The activity of events of the reference subject is stored as a function of event location and is utilized as scale factors for scaling the relative energies of event signals obtained from the living subject, whereby data of the living subject is normalized relative to the reference subject.

Abstract: An array of sonar transducers enclosed within a flexible webbing and having spring members located between the transducers for urging the transducers against the webbing to provide a rigid structure which secures the transducers in their positions in the array. The webbing is stowed in spaces between the transducers with the array being in a compressed attitude and secured within an outer canister to permit air dropping of the array into the ocean.

Abstract: A system providing linear amplification of a signal including a pulse duration modulation of the signal upon a carrier signal, the system further including a plurality of amplifying units which are sequentially activated by the modulated carrier. The amplifying units are arranged in the form of a bridge circuit, the nodes of which are coupled to a load, the amplifying units including transistors which are driven alternately in states of conduction and nonconduction for maximizing power coupled to the load while minimizing power dissipated in the transistors. A filter connected between the amplifying units and the load attenuates signals at the frequency of the carrier so that the waveform of the signal applied to the load duplicates the waveform of the signal at the input of the system.

Abstract: A radiographic camera having a scintillator and an array of photodetectors positioned for viewing a common region of the scintillator, and wherein a mask system is interposed between the scintillator and the array of photodetectors for increasing the resolution of an image produced by the camera. The mask system has a pair of mask plates which are spaced apart and have similar formats of opaque materials thereon. The mask system provides a more rapid variaton in the intensity of light received at a photodetector as a function of locations of scintillations on the scintillator. A reference signal source providing a signal pattern in accordance with the intensity variation is utilized for decoding shadows cast by the mask to produce the image.

Abstract: An imaging system utilizing a scintillation camera for photographing subjects emitting gamma and X-radiation. Masks are sequentially positioned between the subject and the camera to produce a sequence of shadowgrams upon the face of the camera. Output signals of the camera are summed together to give an array of sum signals, the array of sum signals being Fourier transformed followed by a matched filtering by multiplication of the frequency terms by an array of factors utilized in generating the masks. Phase factors are applied to the camera output signals, either before the Fourier transformation or during the matched filtering, the phase factors identifying the masks utilized in producing the respective shadowgrams. An inverse Fourier transformation then results in an image of the subject.

Abstract: An electrolytic measurement system incorporating a probe for the measurement of the conductivity of fluids such as sewage and other industrial effluents. The probe has a smooth surface to passage of the fluid with flush-mounted electrodes arranged serially along the passage. The passage is formed within material that is an electrical insulator and is surrounded by a metallic shield symmetrically positioned with respect to the ends of the serially arranged electrodes. An electric potential is impressed between the outer electrodes and the shield, the latter being grounded, while an inner electrode is used for the measurement of electric current flowing through the fluid from the outer electrodes to the inner electrode.

Abstract: A display and power supply system in which the power supply uses a switching frequency which is higher than the highest linear deflection rate used in a cathode ray tube display device supplied by the power supply and in which the frequency of the power supply and the information repetitively displayed on the display are synchronized to eliminate interference of the power supply frequency with the display characteristics.

Abstract: A system for Doppler frequency measurement, responsive to spectral modulation induced by a reverberant and nonlinear radiation transmissive region such as the ocean, and composed of a Fourier transformer for providing digitally the spectral lines for a set of samples of a Doppler signal, a circuit for obtaining the logarithm of the power spectrum, weighting of the logarithm by othogonal functions, and an arithmetic combination of components of the weighted logarithm.

Abstract: A radiographic camera of the form employing a scintillator for producing optical photons in response to incident gamma and X-radiation, a collimator positioned between a subject emitting such radiation and the scintillator for guiding the radiation to the scintillator, and a detector of optical photons for signaling the positions of points of impingement of quanta of the incident radiation upon the scintillator to produce an image of the subject, the improvement being a Fresnel focussing means located alongside the scintillator for directing the optical photons to the detector. The Fresnel focussing means takes the form of a segmented mirror at the front surface of the scintillator and a Fresnel lens at the back surface of the scintillator.

Abstract: A recorder in which a stylus is transported in successive line scans across a recording medium for imprinting data thereon, a stylus transport having a guide edge with which the stylus makes sliding contact, the stylus transport having a lubricating surface against which the stylus is guided for producing a thin film of lubricant upon the stylus. The lubricating film prevents wear between the stylus and the guide.

Abstract: A radar system having transmitted and received signals, the system including a feedback loop for modulating a sample of the transmitted signal to duplicate the phase and amplitude of the clutter echoes from nearby points of reflection. The modulated transmitted sample is subtracted from the received signal to remove the clutter. The feedback loop detects differences between the clutter-free signal and the transmitted sample to produce an error signal, the error signal being filtered and applied to the modulator for modulating the phase and amplitude of the transmitted sample.BACKGROUND OF THE INVENTIONThis invention relates to echo ranging systems such as radar and sonar systems and, more particularly, to an echo ranging system in which clutter returns from nearby objects are removed from echoes from distant objects.

Abstract: A cylindrical array of radiating elements or sonar transducers each of which is coupled by a clipping circuit to a multiply tapped shift register for imparting delays to the signals of the elements for forming a beam of radiant energy. Sidelobes on the radiation pattern are reduced by multiplying the signals of the shift registers by weighting factors prior to their summation for forming a beam, clipped signals serving as unitary factors of positive or negative sign in the multiplication.

Abstract: A recorder in which a stylus assembly is transported across a recording medium at increased speeds by a flexible non-extensible belt having its edges slidably nested within slots oriented transversely of the recording medium. The belt has molded teeth for accurate mating with a sprocket drive.

Abstract: A gamma camera with a plurality of photodetectors arranged for locating flashes of light produced by a scintillator in response to incident radiation. Masking material is arranged in a radially symmetric pattern on the front face of the scintillator about the axis of each photodetector to reduce the amount of internal reflection of optical photons induced by gamma ray photons.

Abstract: A ranging system, particularly useful for sonic depth sounding employing a receiver utilizing one bit sampling of received echoes. A correlator correlates a sequence of one bit samples against a sequence of reference samples, such a sequence of reference samples being conveniently provided by a transmitter of sound waves. An envelope detector circuit provides the envelope of received echoes and a peak detector provides the time of occurrence of the peak of the envelope. A gate generator responsive to the time of occurrence of the envelope peak provides a gate signal which brackets a succession of output pulse signals from the correlator to delineate coarse range or depth while individual output pulses within the gated interval are applied to a second peak detector to give a range or a depth reading corresponding to the time of occurrence of the maximum output pulse of the correlator.