Abstract: A height finding arrangement for a range/azimuth surveillance radar using a mechanically rotated planar antenna array. The received outputs from the array are combined with suitable weighting functions to give two sectorial pattern signals whose effective phase centers are respectively above and below the center of the array aperture. The phase difference between these two signals is measured to provide the elevation angle of the target.

Abstract: A system for tracking a moving target from a moving carrier. The system is provided with an arrangement allowing a measurement of the position of the target in relation to the carrier. The difference between the position of the target and an estimated position for the latter is given by this arrangement, generally in spherical co-ordinates. These spherical co-ordinates are changed by a co-ordinates converting unit into cartesian co-ordinates. The position of the target is given in turn in relation to a cartesian frame of reference of unvarying orientation whose origin is situated close to the instantaneous centre of rotation of the carrier in relation with a trajectory simulator. The frame of reference is then changed in the opposite direction for a control of the position of the measuring arrangement.

Abstract: A radio direction finding system including a transmitter and associated antenna located at one end of a radio communication path and a receiver and associated antenna at the other end. One of the antennas is characterized by an omni-directional pattern. The other antenna is characterized by a rotating, directional antenna pattern which is periodically reversed in direction at a rate low compared to its rotation frequency, but high compared to changes in bearing occurring between the transmitter and receiver. The periodic modulation of the RF signal caused by the rotating antenna pattern is detected by the receiver which generates a demodulated output signal. This demodulated signal is averaged over a period including the two directions of antenna rotation, with the result that the bearing error portions cancel, yielding a bearing-indicating signal which is relatively free from receiver-introduced phase error.

Abstract: This invention provides a solar energy collector including a Fresnel lens substantially fixed in orientation and position relative to the Earth, a receiver situated at a focal point of the said Fresnel lens, a mounting mechanism which constrains the receiver to move along the focal surface of the Fresnel lens, and orientation means for continually orientating the receiver so that the said receiver remains in a region of high intensity of radiation during periods of direct sunlight.The solar energy collector according to the invention is particularly suitable for inclusion in building structures.

Abstract: Radar wave energy entering aircraft engine cavities is substantially disped by providing within such cavities surfaces having perturbations or dipoles which interact with the electromagnetic energy within the cavity interior, causing the reflected energy to be defocused or scattered over a broad range of angles thereby substantially lowering the radar cross section of the cavities.

Abstract: 1. The combination comprising a pair of magnetic dipole antennae of substantially equal radiation strength in proximate but offset relation and oriented with their axes extending in a common direction, and an oscillating current source operatively connected to both of said antennae to drive them simultaneously but in opposed phase relationship, whereby the dipole moments of said antennae substantially cancel one another so that the antennae function together to produce a magnetic quadrapole radiation substantially free of any dipole movement.

Abstract: A vertical deflection system for a television receiver produces a sawtooth wave signal of a high linearity by high speed charge (or discharge) of a capacitor and a low speed discharge (or charge) thereof at a constant current rate, compares a deflection current flowing in a vertical deflection coil with the sawtooth wave signal in a differential amplifier to correct the deflection current whereby the amplitude and linearity of the vertical deflection are automatically corrected. The amplitude of the vertical deflection can be adjusted without affecting other characteristics.

Abstract: A pair of antennas mounted on a vehicle receive an echo wave reflected from an obstacle to produce a pair of Doppler signals, the variation of the phase difference of which is used to indicate the direction of the relative movement of the obstacle. The phase difference also represents the difference in propagation lines and is proportional to the relative angular displacement of the obstacle so the rate of variation of relative angular displacement is detectable because the increase and decrease of phase difference negate each other.

Abstract: A system for compensating for cross polarization coupling in a dual-polarization satellite communication system, in which two polarized waves of the same frequency and orthogonal to each other are alternately transmitted as a pilot wave from an earth station at a predetermined period. The same polarized wave components of the two signals received by a communication satellite are sent back to the earth station, so that the sent back signal is received by the earth station. An amplitude ratio and a phase difference between the same polarized wave components of the two signals of the received pilot signal are detected. A communication signal wave to be transmitted from the earth station is formed as an elliptically polarized wave by the use of the detected information, thereby compensating for cross polarization coupling of the communication signal wave caused during propagation between the earth station and the communication satellite.

Abstract: A continuous wave frequency modulated signal is radiated from a range rate measuring system and returned by a target, the range rate of which, relative to the measuring system, is to be determined. The radiated signal and return signal are mixed to produce a beat frequency signal which is converted to a square wave signal marking passage of the beat frequency signal above and below its average value. A detector produces signals indicative of the presence and absence of transitions of the square wave signal at the turnaround points of the modulation waveform. The range rate of the target is directly related to the rate of the presence and absence of such signals.

Abstract: In marine seismic exploration, seismograms recording reflected energy generated from the firing of a seismic source are used to measure the characteristics of the medium through which the energy passes. These measurements are converted into control parameters for an array of seismic sources. When the array is fired under control of these parameters, seismograms having enhanced reflections are produced. As an example, at least one seismic source is fired to produce seismograms which are used in the measurement of water bottom reflectivity and water depth. The measured reflectivity and water depth are converted into a time domain operator representative of the inverse of the reverberation distortion in the water layer. An array of sources is then fired in a sequence which produces an acoustic pressure wave having the inverse time domain characteristics.

Abstract: In an ultrasonic antenna assembly specifically adapted for use in a material level control system and of the type which includes a parabolic reflector and an ultrasonic energy source mounted at the parabolic focus and directed to radiate energy toward the reflector surface from the direction of the parabolic axis, the improvement comprising a sonic absorber of low-density fiberglass disposed at the reflector surface opposite the energy source to absorb energy directed onto said surface from said source, such that multiple reflections between the energy source and the reflector surface are inhibited.In a modified embodiment the parabolic reflector and energy source are adapted to be mounted in the upper portion of a storage tank such that the parabolic axis is substantially horizontal, and a plane reflector is disposed adjacent the parabolic reflector at an angle of forty-five degrees with respect to the parabolic axis.

Abstract: Disclosed is an automatic gain control (AGC) circuit for an IF amplifier utilized in the receiver of a pulsed radar. The AGC circuit is provided with a noise measuring circuit for determining the minimum value of a number of average noise levels over corresponding time intervals of given short duration within the length of time for the range-independent RF signal amplification in the pulse repetition period. Such a noise level, based on the minimum value, can be considered to be least influenced by rain clutter. The IF amplifier is adjusted to this noise level.

Abstract: A multi-beam satellite switching system employs onboard switching for the purpose of increasing the up path and down path antenna gains. A multiplicity of up path antenna beams and of down path antenna beams (not necessarily the same number of each direction) are provided by the system. A number of amplifier systems are distributed across the frequency band of interest. These amplifier systems comprise input amplifiers including filters, frequency converters and output amplifiers. A switching and control circuit accepts an up path signal from only the desired input amplifier and connects the desired output amplifier to the desired down path beam. Each earth station transmits to the satellite a suitable signal to perform the desired switching functions.

Abstract: A high voltage generating apparatus suitable for a television receiver. A flyback transformer has a secondary winding divided into a plurality of parts by at least a diode and a primary winding connected to a variable voltage divider circuit for varying the primary-side flyback pulse voltage. The variable voltage divider circuit is connected to an end of a focus capacitor with the other end thereof connected to the cathode of the diode, so that a variable pulse voltage is applied to the focus capacitor to regulate the focus voltage.

Abstract: The application relates to a thyristor-controlled horizontal deflection circuit of a television receiver with mains isolation. Input inductor, communtating inductor, and isolation transformer are united in one component. In the transformer used for this component, the open-circuit inductance performs the function of the input inductor of a conventional thyristor horizontal deflection circuit, and the short-circuit inductance that of the commutating inductor.

Abstract: An arrangement for protecting radars against unwanted echos such as "clutter" using an angular divergence measuring signal. This signal is compared with two predetermined thresholds + xo and - xo. When the probability of the two thresholds being exceeded by the divergence signal is greater than a predetermined value Po, the arrangement generates a logic signal which is used to prevent the tracking circuits of the radar from locking on to the received echo.

Abstract: In the method, useful signals from an originating station are enveloped by counter-counter measure additional signals, independent of the useful signals, transmitted from the originating station independent of the locating and transmission system, and effective to force a jammer, having a limited available jamming power, to diminish or shift the density of its spectral jamming output. The useful signals are enveloped in a time range, a frequency range, and/or a spatial range, and the useful signals and the additional signals may have frequencies which differ from each other. In one embodiment of the apparatus, the useful signals and the additional signals are supplied to respective inputs of a multiplexer whose output is connected to a transmitter connected to a radiator which may be either an optical radiator or an electromagnetic radiator.

Abstract: The invention relates to an arrangement for suppressing the echos received in the side lobes of a main antenna of a radar system. An auxiliary antenna, whose diagram overlaps with the side lobes of the main antenna, supplies a signal B which is compared with the signal A from the main antenna. The comparison is performed between microwave signals or intermediate frequency signals by means of an operating circuit which emits signals S.sub.1 = A + k.sub.1 B and S.sub.2 = k.sub.2 (A - k.sub.1 B) where k.sub.1 and k.sub.2 are amplitude and phase modifying complex coefficients, and an amplitude and phase demodulating circuit which receives S.sub.1 and S.sub.2, one of which may possibly be in phase quadrature. The presence of an off-center echo, for example, results in a threshold being exceeded by the filtered demodulated signal.

Abstract: A marine gun for the production and timing of underwater pulses by the discharge of gas under pressure comprises a body having at least one port, means retaining the gas in said body under pressure and for allowing it to discharge through said port to produce said pulses, said gun including at least two electrodes which make electrical contact with the water in the path of gas discharged through said port such that such a discharge of gas increases the electrical resistance between said electrodes to produce a timing signal.