Abstract: A combined adaptive sidelobe canceller and frequency filter system eliminating the narrow band interfering signals by use of the adaptive frequency and eliminating the broad band interfering signals by the adaptive sidelobe canceller.

Abstract: A privacy communication method and system which utilizes coherent, continuously changing frequencies for keyed, pulsed, and voice communications. A synthesized swept frequency or "chirp" signal imparts a privacy or secure communications capability to the communications signal by virtue of the random or pseudo-random nature of the transmitted signals which is programmed.

Abstract: An apparatus for pulsing a high speed transmitter having pulser delay times in the nanosecond range. The combination of solid state and spark gap devices provide protection against high voltage arcs for both transient and power follow-through conditions.

Abstract: Apparatus for terminating teletype signal lines and mixing cryptographic teletype signals to furnish an enciphered teletype signal including a secondary operating mode of the mixer unit to retransmit the incoming teletype signal in the event enciphering or deciphering is not required.

Abstract: Spurious frequencies are eliminated in a direct frequency synthesizer by means of a feed forward correction circuit. The improved direct frequency synthesizer of the invention includes a series adder, clocked register, a D/A converter and a phase corrector. The adder is inputted by a digital control increment and the output of the register. The system clock frequency is divided down by a smoothing counter that in part controls the phase of the output signal. Spurious frequencies are manifested by overflow of the register. The register overflow is converted to an analog signal by the D/A converter. The system output is provided by a voltage controlled oscillator that is controlled by an amplifier which is responsive to both the smoothing counter output and the analog output of the D/A converter. Additionally, the D/A converter is sampled twice for every cycle of output frequency, resulting in a doubling of the output frequency for a given D/A converter.

Abstract: A dual frequency band directional antenna or system in the form of a cavity reflector antenna mechanically combined and radiation-coupled with a loop of approximately the same shape and periphery as the rim edge of the cavity reflector, which loop is arranged outside and in front of, and in close proximity and parallel to the cavity rim edge, and, when properly energized, acts for the lower frequency band as a loop radiator with preselected field polarization, whereby the entire cavity structure serves two purposes by acting simultaneously as reflector for the higher frequency band cavity reflector antenna and for the lower frequency band, electrically separate loop radiator, with the radiation patterns of both sources being unidirectional over both frequency bands and with their radiation maxima directed into the center axis normal to the bottom plate of the cavity reflector structure.

Abstract: 1.

Abstract: A high power pre-TR switch utilizes hot pressed boron nitride to form a vial. The vial contains a halogen gas such as chlorine.

Abstract: The repetition frequency tracking apparatus utilizes the input signal to start a timer to provide the correct phase. When the timer sweeps through the right frequency, the tracker will lock to a single pulse train within a two octave frequency spectrum. After the lockup, the tracker is switched to a free running mode to provide pseudo synchronous running through durations of missing input pulses. Accurate tracking is provided by the use of an early late gate phase discriminator for phase sensing and correcting to zero, errors at all locking frequencies.

Abstract: A switch debounce circuit buffers the mechanical contacts of a double throw single pole switch into digital logic. It is essentially an active debounce circuit requiring only one wire from the switch to the circuit. The circuit includes a pair of oppositely connected inverting logic amplifiers with a resistor coupled between the output of one amplifier and the input of the second amplifier. The input from the switch is connected to the same leg of the circuit as a resistor and the output is taken from an opposite leg connecting the output of the second amplifier to the input of the first amplifier. The propagation of logic signals is effected by changing the state of the switch but contact bounce does not effect the logic.

Abstract: A nonlinearly variable gain circuit is utilized to produce an inverted logarithmic S curve of gain versus potentiometer rotation while using a linear resistance taper potentiometer. An operational amplifier feedback circuit uses the linear potentiometer and a resistance network in combination.

Abstract: A radiation dose rate hardened light detector uses a Schottky diode island on a sapphire substrate. The thickness of the silicon is carefully adjusted to produce interference absorption at the light wavelength of interest. The light enters the silicon through the sapphire and is reflected off a metal electrode to produce the interference at the silicon-sapphire interface.

Abstract: An integrated quantized signal smoothing processor samples an analog signal, converts it to a digital number and averages n samples, the averages of n equal or nearly equal signals will be quantized with the quantization interval of an A/D converter. An improvement signal is added at the input of the A/D converter with the output quantization interval becoming q/n. For a given accuracy, the improvement permits a lower number of bits in the A/D converter.

Abstract: An RF intruder system utilizes two concentric loops of wire spaced apart for a predetermined magnitude, either of which can transmit and/or receive electromagnetic energy. This area within the loops are to be protected against intrusion. Without intrusion, the received signal is steady. Upon intrusion, there are signal changes which are instantly noted by signal detection and processing.

Abstract: A radar intrusion detection system for isolated resources uses only one bistatic radar in combination with multiple passive reflectors to define the zone to be protected. Any intruder crossing a boundary of the zone within which is located the isolated resources interrupts the radar beam and thus may sound an alarm.

Abstract: A system is provided for multistation remote position indication for remotely controlling and indicating the position of a motor driven positioning system, particularly an antenna rotor, at multiple locations utilizing a single pair of control wires to interconnect all remote control units. The system includes the generation of a symmetrical alternating polarity low frequency pulse train which is amplitude modulated by the position of the antenna, display of the antenna position by means of a polarity selective peak detecting voltmeter, and control of the antenna position by means of polarity selective current means through a synchronous detector and antenna drive motor control means.

Abstract: A charge-transfer voltage converter transforms a high voltage to a lower value without the use of a conventional transformer. Two capacitors are connected together to form an electrical circuit. The circuit is then broken in one place and a switch is inserted to form a continuous circuit. One of the two capacitors is charged to a high voltage. The switch is turned on and off rapidly and this transfers a charge from the charged capacitor to one which was initially uncharged. By controlling the duty cycle and/or repetition rate of the switch between the two capacitors, the output voltage of the capacitor which was initially uncharged can be maintained between the limits of zero volts and the value to which the supplying capacitor was initially charged. Thus, voltage transformation has been achieved without the use of a conventional transformer.

Abstract: A differential tri-phase shift keyed modulation system permits both data and data synchronization signals to be transmitted at a single frequency which are then differentiated by phase.

Abstract: An optical position pick-off for proof-mass in a zero-drag satellite is obtained by placing a spherical mass shielded from all forces except gravity, between a flat screen having four equally spaced photodetectors and a light source. The mass interrupts the light beam and casts a circular shadow on the screen, the periphery of which passes through the center of each of the detectors. A shift in the mass in any direction causes its shadow to cover more of certain detectors and less of others or more of all or less of all. The unbalance of the detectors may be used to actuate small jets to change direction of the satellite until the mass returns to its null position.

Abstract: A constant impedance, constant phase PIN diode attenuator uses PIN diodes in a double pi configuration. A control voltage is applied simultaneously thereto thus attaining 40 dB attenuation without substantially varying phase and amplitude characteristics.