Abstract: A doubly-ridged waveguide device acts an an electrical-length equalizer or hase compensator for a pair of horn antennas of different physical length and/or aperture size. The phase compensator comprises a central doubly-ridged waveguide section with a uniform cross-sectional area and two similar doubly-ridged tapered waveguide transmission lines with cross-sections and ridge depth that continuously vary, located at either end of the central section. The width of the ridge is constant along the entire length of the structure. The device is connected in the standard waveguide transmission line of the smaller of the two horns.

Abstract: An orientation system adapted to be mounted within a vehicle, comprising a display including a rotational heading indicating compass card fabricated from an image retaining electronic display panel responsive to bearing data signals.

Abstract: A correlation receiver for detecting and measuring the angle-of-arrival of adio frequency signals, including two antennas, a correlation processor, and a CRT display.

Abstract: Disclosed is an electronic signal processing system for an alternating voltage input signal. A phase-locked loop network has an input adapted to receive the signal and produce an intermediate signal comprising a substantially noise free sine wave with a phase equal to the average phase of the input signal. The intermediate signal is applied to an input of a variable gain amplifier which produces an output signal proportional to the intermediate signal, and an amplitude averaging loop network has the input signal and the output signal as its inputs and produces a biasing signal which is applied to a control input of the variable gain amplifier to maintain the output signal equal in amplitude to the average amplitude of said input signal. The system can be used in a Watson-Watt type radio direction finder to eliminate noise.

Abstract: A fixed array of three identical directional receivers, each having a carid directional pattern, are arranged in a symmetrical configuration with each receiver having its principal axis of maximum sensitivity oriented 120.degree. from the corresponding axes of its neighbors. By comparing the relative magnitudes of the voltages generated in each of the three cardioid receivers upon receiving a signal, the bearing of the signal source is automatically determined and displayed. The tri-cardioid receiving array overcomes the prior art need for large-sized directional receiving transducers, and also overcomes the need for mechanically rotating or electronically scanning the receiving array to find the bearing of the signal source.

Abstract: An electronic navigation system ground station, which may be either an omni-range beacon (such as VOR) or a passive direction finder. A circular array of antenna elements has a feed arrangement which includes switched programming of at least one discrete set of phase shifters to effect successively changed phase-rotation fields for minimizing the adverse effects of multipath signals between the ground station and a remote station, aboard an aircraft for example.

Abstract: A pulse radar device had pulsed storage devices which are arranged in the signal analysis component and comprise, in particular, shift registers. The clock frequency for the shift registers is derived from a reference frequency. Within the radar period duration, a first time zone is defined as the actual analysis zone and signal processing is carried out with the clock frequency predetermined by the requisite range resolution, and a second time zone is defined (dead zone) in which a different clock frequency is selected.

Abstract: A collision avoidance system using on-board B-CAS equipment having an object to minimize interference with the ground SSR stations and to effect precise tracking or distance-altitude measurement when necessary. Normally passive surveillance is made to detect the presence of other aircraft in the B-CAS range. Active surveillance is added when required. In the active surveillance mode, initiated on locating an intruder aircraft, the power and interrogation signal are varied when the intruder aircraft becomes a threat aircraft to minimize interference with the ground SSR stations and aircraft outside the threat zone while maintaining accuracy of detection and tracking of the threat aircraft at a high level.

Abstract: A Loran-C antenna and coupling circuit therefor are disposed at a given site, the antenna and coupling circuit therefor being capable of both transmitting and receiving. A first circuit is disposed at the given site coupled to the antenna coupling circuit to detect far-field remote signals and a second circuit is disposed at the given site coupled to the antenna coupling circuit to detect far-field local signals.

Abstract: A method for locatingweak targets such as power lines and tree tops in the presence of terrain clutter by separating the weak target from the clutter in the elevation plane.

Abstract: A system for providing aircraft guidance at elevation angles less than the transmitting antenna beamwidth.

Abstract: Passive frequency measuring circuit comprising a number of frequency discriminators to obtain a digital code representing the frequency of an applied r.f. signal. Each discriminator is tuned to different frequency ranges, and provided with a plurality of similar frequency analysers for the phase detection of the applied r.f. signal passed through different delay lines. As each discriminator delivers an ambiguous code at the boundaries of its characteristic, a digital filter is incorporated to resolve the ambiguity. If such an ambiguity is established, an adjoining discriminator is activated to deliver information for obtaining a digital code representing an unambiguous frequency value.

Abstract: A system in which the characteristics of a microwave power transmission beam are controlled in accordance with power distribution profiles altered due to the detected presence or entrance of an object into the beam which causes changes that are perceived in various received, reflected and scattered power distribution profiles resulting over various receiving elements of the system. An analysis of these changes is made, the results of which are used to reshape, dim or douse the power beam in accordance with predetermined criteria. Additionally, a "FAIL SAFE" condition is obtained by employing a beam penetration tester, whose function is to repeatedly test the correct performance of the beam intrusion detecting scheme by presenting a minimal threshold scattering or absorbing cross section while crossing the power beam. If the beam penetration tester is undetected by the beam safety system, then the beam control is preconditioned to turn off the power beam.

Abstract: The invention relates to a system for the reception, storage and subsequent ransmission of information. The system utilizes a main memory and an auxiliary memory. The information received by the auxiliary memory updates and corrects the information in the main memory. A timing generator controls the timing of the memory scan periods and a time normalizer is utilized to correct frequency deviations of the timing generator. A detector monitors the operation of the system.

Abstract: Complex modulation--that is, amplitude and phase modulation--is used to provide smaller beamwidth and better angular resolution of a scanning radio beam generated by a commutatively switched aerial. The way in which the modulation pattern may be determined is detailed, and examples are given of the application of complex modulation techniques to different types of commutative aerials.

Abstract: In an information receiving apparatus having a time-shared mode of operation for simultaneously receiving a plurality of information carrying signals, at least one signal of which includes an identification tone superimposed thereupon, a tone reconstitution scheme for providing a continuous tone from a received tone signal which contains absences of tone signal due to the time-shared partial duty dedication of the receiver to that signal and its superimposed tone.

Abstract: A general aviation navigational receiver is provided with a digital channel selection wherein a channel selection knob on the aircraft control board may be operated to control the functioning of a digitally implemented frequency synthesizer which in turn controls the operation of a voltage controlled oscillator for providing frequency signals to an RF mixer of the unit, the frequency synthesizer being programmed for both possible VOR/LOC and GS channel frequencies wherein switching between frequencies is accomplished in synchronism with the basic clock within the synthesizer greatly reducing transient changeover time.

Abstract: The invention provides a side-looking coherent pulse radar for use on a moving platform and for exploring space laterally with respect to the displacement of the platform. The receiver includes a detector which coherently detects echo signals having a Doppler component and applies these to a correlation processor which samples the detector output signals and performs a correlation process with a reference correlation waveform having a center frequency which is chosen to bear a predetermined relationship with the Doppler frequency component of the received echo pulses. Sensors derive the accelerations of the platform in three mutually orthogonal planes (one of which is in the platform displacement direction) and the parameters derived by the sensors are utilized to maintain the aforementioned predetermined relationship as the Doppler frequency component of the echo pulses vary with movement of the platform from the required displacement direction.

Abstract: An AFC system for a radar comprising means for changing in one sense a control voltage fed to a voltage controlled local oscillator forming part of the radar receiver when a predetermined number of cycles of a difference frequency between a local oscillator and a transmitted radar frequency obtain during a predetermined period until less than the predetermined number of cycles obtain whereupon the voltage is changed in the opposite sense whereby the frequency of the local oscillator is automatically controlled.

Abstract: A series coupled inductance and active current conducting device are coupled in parallel with a winding of an output transformer of a horizontal deflection generator. Flyback pulses integrated in sawtooth waveforms are combined with a vertical rate parabolic waveform derived from a vertical deflection generator and coupled to a control electrode of the active device for controlling its conduction during each flyback interval at a vertical rate for loading the output transformer and thereby altering the horizontal scanning current in a manner to correct for side pincushion distortion.