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: An electronic license tag or plate formed into a unitary structure and including a single antenna system cooperating in a system comprising a harmonic radiator which transmits a pulse coded identification signal in response to an interrogation signal, and in a signal communication path for detecting and decoding code modulations in the interrogation signal and deriving therefrom an information signal which is communicated to the operator of a vehicle to which the tag or plate is affixed.

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: 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.

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: A receiver of ultrasonic pulses having a known pulse width and at a known spacing includes a gate which is normally conditioned to accept the ultrasonic pulses. When the first pulse is received, however, the gate is opened thereafter only when subsequent pulses should be present and is closed when no pulses are expected. Such an arrangement prevents multipath signals being interpreted by the receiver as information.