Abstract: An improved transmitter having protection from undesired out-of-band radiation caused by high frequency components in a supplied signal to be transmitted uses means for determining when the supplied signal is such as to cause out-of-band radiation. A resulting control signal then reduces the amplitude of the higher frequency components of the supplied signal relative to the remainder of the signal, thereby preventing out-of-band radiation.

Abstract: A method and apparatus for performing integration using a circuit capable of integrating an input signal over a wide linear dynamic range. The circuit modulates the input signal with a biphase signal having positive and negative phases. The modulated signal is then provided to an integrator. The integrator operates continuously within its linear range without needing charge dumping because the amplitude of the modulated signal is less than the amplitude required to saturate the integrator. Each interval of the integrated signal corresponding to positive and negative phases of the biphase signal is then partitioned into intervals corresponding to the positive phase and intervals corresponding to the negative phases by two track and hold circuits with alternating tracking and holding periods. The signal intervals corresponding to the negative phase of the biphase signal are subtracted from the intervals corresponding to the positive phases by a differential amplifier.

Abstract: Successive MLS scanning signals are received as pulse-type analog signals and converted into corresponding digital signals. The centroid of each digital signal is determined at at least two different levels below the peak of the digital signal. The centroids for each signal are averaged, whereby the average represents the centroid of the corresponding received pulse-type signal.

Abstract: A central aperture provides at least two radiation pattern modes. A second aperture concentric with the central aperture provides at least two radiation pattern modes. A first feed system excites the central aperture and a second feed system excites the concentric aperture. Circuit means associated with the second feed system provides an auxiliary excitation to the concentric aperture which results in optimizing the radiation pattern obtained during excitation of the central aperture.

Abstract: A beamforming adaptive control loop is simultaneously employed in combination with a null-steering adaptive control loop to enhance the signal/interference ratio resulting in an increase in the messasge quality. The loops may employ temporal processing in which case on-epoch sample/hold filters and off-epoch sample/hold filters form separate loops which enhance the desired signal and cancel the undesired signal, respectively. The correlated output from the beamforming loop is added to the correlated output of the null-steering loop and mixed with the incoming signal.

Abstract: An improved asymmetrical sideband amplitude modulation (AM) transmitter is provided wherein the resulting transmitted signal produces a pleasing pseudo-stereo effect when received by a stereo receiver of the type designed to receive symmetrical sideband, phase-separated AM stereo radio braodcasts, when such receiver is operating in its stereo mode.

Abstract: In order to recover the original audio modulation samples when using a continuous code change, sampled data, spread spectrum waveform structure, a dedicated message matched filter is used to process data from multiple emitters within the same range interval. The dedicated message matched filter is matched to an incoming signal only at the precise time of the message epoch. The matched filter coding corresponding to the arrival time of message epochs as derived from synchronization acquisition circuitry is rapidly switched so that one dedicated message matched filter can be used to process data from multiple users simultaneously.

Abstract: A system for synchronizing a succession of horizontal deflection coil currents of a CRT display with a succession of synchronization signals includes a variable delay which is strobed by a synchronization signal and triggers the generation of a deflection current after a specified delay. The delay is automatically controlled by a feedback loop in which the present delay is measured by a set-reset flip-flop, the flip-flop providing an output pulse having a duration equal to the delay. An integrator averages a train of output pulses from the flip-flop, and combines a reference signal with the average value to provide the control signal for the delay. The system operates with minimal bandwidth and with dynamics which are free of acquisition constraints so as to provide minimal sensitity to noise.

Abstract: A remote monitoring system (RMS) receiver which operates at a dual baud rate. The operating rate is selected to be the same as the rate being used by remote equipment originating the data link with the receiver. A modem associated with the receiver provides an indicator signal indicating phase shift keying (a high baud rate) or frequency shift keying (a low baud rate) is being received from the remote equipment. The indicator signal is used to select the baud rate of a programmable baud rate generator of the RMS receiver. This controls the baud rate signal which is supplied to an asynchronous interface controlling data transfer between the receiver and the modem.

Abstract: Proper operation of a beam steering unit for a phase array antenna, is verified by simulating the pattern of wave energy which would be radiated to an observation point in space when the beam steering unit is connected to phase shifters associated with elements of the antenna. The simulated pattern thus obtained may be compared with a preset pattern for the observation point during a scanning operation of the beam steering unit, and an alarm or other indication is obtained when the difference between the simulated and the preset pattern exceeds a certain limit. The simulated pattern is obtained by storing phase angle data from the beam steering unit in a memory at areas corresponding to phase shifters associated with elements of the phased array antenna.Observation angle data corresponding to the angle of the point in space relative to the antenna array is generated, the observation angle data being a function of observation angle, antenna element spacing and radiation wavelength.

Abstract: A color monitor having a highly accurate video processing circuit for providing a high accuracy color CRT display is disclosed which utilizes three feedback loops in each of the three primary color channels, each feedback loop including both the final video amplifier and the CRT in order to achieve equalization and stabilization of their combined signal-to-brightness transfer characteristics against both CRT and circuit drift. The video processor circuitry also includes a D/A converter for generating a signal representative of the desired amplitude component for each primary color from a three bit digital input. By utilizing the three feedback loops, the color produced in the CRT display is independent of the operator set brightness and contrast settings and is maintained to within 10% of its desired value over varying temperature and adverse environmental conditions.

Abstract: A transistor circuit is provided with a symmetrical floating configuration for attaining multifunction operation of a transistor having symmetrical source and drain characteristics, preferably a GaAs MESFET. The circuit includes a balun which may be configured as a transformer, a differential amplifier, or a magic-tee waveguide depending on the frequency of signals to be processed by the circuit. Balanced terminals of the balun may be directly or capacitively coupled to source and drain terminals of the transistor. Tuning circuits are employed for applying signals having different frequencies to the transistor and for extracting intermodulation products generated by the transistor in response to the signals at the different frequencies. With the direct connection between the balun and the transistor, alternating voltages may be impressed between the terminals of the transistor to alternate source and drain regions of the transistor.

Abstract: The amplitude of a signal to be modulated on a carrier wave is sampled every T seconds. The sampled amplitudes are converted into phase representative pulses of pulse rate 1/T. Each phase representative pulse corresponds to the difference between a first phase corresponding to the sampled amplitude and the phase of Nth previous phase representative pulse, where N is an interger greater than 1. The discrete phase representative pulses are phase modulated onto the carrier wave. Conversion is accomplished by detecting the sampled amplitudes, applying the detected amplitudes as an address to a ROM to provide corresponding differential phase information, and modulating the differential phase information onto the carrier. To demodulate the signal from the carrier wave, the carrier wave is delayed for NT seconds and the delayed signals are subtracted from the undelayed signals.

Abstract: Proper operation of an RF diode digital phase shifter of the kind having a number of logic inputs to effect corresponding incremental shifts in the phase of an RF signal passing through the phase shifter, is determined by monitoring the voltages developed across resistance elements of driver stages associated with diodes of the phase shifter. Voltages developed across the diodes are monitored, while turning the driver stages on and off in certain sequences and comparing the levels of the monitored voltages with preset reference levels. The drive stages also can be tested by turning them on and off simultaneously. A fault condition is indicated when the monitored voltages deviate from preset levels.

Abstract: A color video monitor is disclosed which includes improved digital convergence using a plurality of memory means in which vertical convergence correction values are stored, one memory each for red, green, blue and lateral blue convergence values. Interpolation means provide additional values between the points stored in memory such that a smooth transition between successive lines of the display is achieved. The correction values stored in the memories are generated by means of a high-order polynomial function. The monitor employs synchronization circuitry which synchronizes all digital components to the supplied video signal including horizontal and vertical sync pulses and an external 36 MHz clock associated therewith.

Abstract: A microwave landing system incorporates a set of antennas for the sequential transmission of guidance signals through a sequence of directions to enable the reception and decoding of the signals by an airborne receiver. Circuitry is included for the retransmission of a frame of the signals by a procedure wherein the directions of transmissions is altered so as to increase the guidance sector over which the receiver is effective.

Abstract: An apparatus for the stable support of a structure, such as an antenna, in a fluid medium, such as the ocean. A flotation bag supporting an antenna is stabilized by the following features, which can be used individually or in combination. A partially submerged ribbon fence supported by a submerged damper skirt dissipates the kinetic energy of the flotation bag caused by the movement of the ocean and water that encroaches upon the bag. A flexible connection between the bag and the payload enables the bag and the payload to undergo limited motion without affecting each other. Thus, the bag's motion is decoupled and totally independent of the payload. The housing which supports the payload has a flooded chamber, lowering the center of mass of the apparatus. The bottom of the flotation bag is inwardly arched, moving the bouyancy away from the center of the bottom of the bag, enhancing stability and allowing the bag to float lower in the ocean, keeping the damper skirt submerged. The payload includes an r.f.

Abstract: A color video monitor is disclosed which includes improved digital convergence using a plurality of memory means in which vertical convergence correction values are stored, one memory each for red, green, blue and lateral blue convergence values. Interpolation means provide additional values between the points stored in memory such that a smooth transition between successive lines of the display is achieved. The correction values stored in the memories are generated by means of a high-order polynomial function.

Abstract: A scanning system for a phased array antenna for operation at a selected frequency between a first frequency and a second frequency includes the storage of phase shift command signals for each of the phase shifters coupled to radiating elements of the antenna. The memory which stores the phase shift commands is addressed sequentially to provide for a step-wise scanning of a beam of radiant energy at a first frequency of the antenna. The addressing is accomplished by incrementing a count resulting from a counting of clock pulses. Compensation for the stepped positions of the beam for the difference between the selected frequency and the first frequency is accomplished by altering the number of pulses which increment the count of the addressing. The altering is accomplished by the storing of sequences of clock pulses at varying temporal spacings which are used for gating out selected ones of the incrementing pulses.

Abstract: A beamforming adaptive control loop is simultaneously employed in combination with a null-steering adaptive control loop to enhance the signal/interference ratio resulting in an increase in the message quality. The loops employ spectral processing in which case bandpass filters and notch filters form separate loops which enhance the desired signals and cancel the undesired signals, respectively. The correlated output from the beamforming loop is added to the correlated output of the null-steering loop and mixed with the incoming signal.