Abstract: A dual-spin spacecraft having a momentum wheel spinning relative to a platform to provide bias momentum utilizes cross products of inertia (POI) existing in the platform between the spinning axis and the transverse axes to achieve nutation damping. When the platform is rotating or is displaced from a reference the cross products of inertia are also rotating or are displaced causing thereby degradation of the optimum nutation damping time constant. Two or more phase shifting networks are provided to be sequentially coupled into a control loop to shift nutation signals to effect optimum nutation damping at selected positions of the rotating or displaced platform without substantial nutation damping time constant degradation.

Abstract: A sum channel waveguide is excited in a TE.sub.11 mode to cause a radio frequency wave to propagate therefrom through a cylindrical multimode waveguide. The wave propagates via a discontinuity that causes the multimode waveguide to be excited in the TE.sub.11 mode and higher order modes. The multimode waveguide is coupled to free space via a dielectric lens and a cup shaped matching section, whereby the wave causes a beam to be radiated from the lens. The cavity of the multimode waveguide is contiguous with a plurality of arcuate cavities of a difference channel waveguide. The beam is deflected in response to excitation of the arcuate cavities.

Abstract: A radio frequency burst signal memory system is described which includes a feedback loop for recirculation of the received RF burst signal when a proper burst signal is detected. The output from an RF amplifier is split into separate frequency bands by a diplexer. When one of these bands is sensed at the input, only signals of the sensed frequency band are recirculated.

Abstract: Apparatus for optically recording and reading information on a disc medium rotating surface. The information is recorded on concentric or spiral tracks continuously or in parts. The information, which can represent, for example, television video, x-ray, or digital data signals, are addressed by codes that identify the track on which the information is recored preceded by the address code. The recording mechanism can record a new track adjacent to the previous track if the disc has been moved between recordings. There are also means for compensating for eccentricity errors introduced by small changes in the radial dimensions of the disc. The spacing between tracks is typically 2.5 microns although the eccentricity errors may exceed the span of ten tracks. Typically, 4,000 tracks per cm can be recorded.

Abstract: Spacecraft nutation caused by applying propulsive forces to a spacecraft along an axis which does not pass through the spacecraft's center of gravity is eliminated by a signal responsive control system which operates the propulsive forces for a predetermined time period which corresponds to an integral number of nutation periods.

Abstract: In an interrogation vehicle, a receiver of data from a plurality of remote vehicles such as aircraft or maritime vessels in a cooperative collision avoidance system is arranged to receive such data reply signals in reply to interrogation signals. The reply signals are suitably coded in the remote vehicles to provide information in a predetermined plurality of sequential replies from each replying vehicle.

Abstract: A frequency-modulated continuous wave (FM-CW) ranging system wherein continuous feedback to the FM oscillator of the system eliminates drift in frequency excursions of the FM waveform.

Abstract: A frequency-modulated continuous-wave collision avoidance radar responsive to both reply signals from cooperating (tagged) targets and to skin reflections from proximate non-cooperating (non-tagged) targets.

Abstract: A controlled interval pulse train generator comprising a plurality of three terminal transferred electron logic devices, and a delay line. The generator produces a train of small pulse-width voltage pulses at intervals determined by the delay line. The pulse train is started in response to an initial pulse and is terminated in response to a voltage step.

Abstract: A linear amplifier for an amplitude modulated RF input signal wherein the DC output-port bias voltage is varied in accordance with the current into the DC output-port to prevent amplitude and phase distortion of the output signal. Amplifiers utilizing bipolar and field effect transistors are disclosed.

Abstract: A semipassive responder for use in a communication system wherein an interrogating unit transmits an interrogation signal to illuminate the responder. The responder generates, in response to incident interrogation signals, a phase-coded reply signal, utilizing a low voltage, low power-drain reflective varactor phase modulator.

Abstract: One or more satellites are stored or parked in a quasi-equatorial orbit in an inoperative or nonoperating state for subsequent operation in an equatorial plane at synchronous altitude and maintained in that plane thereafter by north-south station-keeping control systems. The satellite is launched in a slightly inclined orbit relative to the equatorial plane of the earth to limit the inclination that may be induced by perturbations for significantly long periods of time during the stored or parked mode without the need for north-south station-keeping control systems aboard the satellite for orbit adjustments.