Abstract: The invention relates to an improvement in radar indicators with digital processing of the signal wherein the raw video signal is firstly digitized and stored in temporary memories for subsequent readout at a rate lower than the writing rate, and for some ranges the readout is repeated for more than one time; further for long ranges it includes a pulse stretcher for increasing the brightness of faraway targets; and finally an anti-interference digital processing including a non-linear transfer function of the digitized video signal which is then converted back into analogue video signal for display.

Abstract: A television display arrangement includes a kinescope comprising a viewing screen, an in-line electron beam gun assembly for producing a plurality of electron beams and an envelope defining a neck, at one end of which the electron gun assembly is mounted. A deflection yoke is associated with the kinescope for producing astigmatic deflection fields for substantially converging the beams at all points on the viewing screen. The astigmatic fields have balanced nonuniformity functions with low peak excursions for reducing the sensitivity of the beam convergence to the position of the yoke relative to the electron beams, by which relative movement between the yoke and the kinescope does not substantially affect the convergence.

Abstract: A sweep generator for producing a circular raster of curved scanning lines on the target surface of a video camera is disclosed. Each curved trace follows a substantially circular path through a scanning angle of 360.degree.. The circular raster is generated by horizontal and vertical scanning signals which are synchronized with the horizontal line frequency of a video receiver. The horizontal scanning signal is characterized by a constant amplitude component followed by a sine wave component, and the vertical scanning signal is characterized by a composite waveform including a constant amplitude component followed by a sine wave component which is shifted 90.degree. in phase with respect to the sine wave of the horizontal scanning signal.

Abstract: An apparatus and method for detecting the polarization of signals reflected from targets immersed in clutter. Signals reflected from targets illuminated with quasimonochromatic electromagnetic signals such as FMCW radar are received by antennas responsive to orthogonally polarized components of the reflected signals. These received orthogonal signal components are then modified such that one component is phase shifted with respect to the other signal components, and the amplitudes of the signal components are varied according to predetermined angles of polarization. The resulting signals are further analyzed in a processor which detects the polarization of the reflected signals by estimating the Stokes parameters for the reflected signal. The Stokes parameters may then be used to generate detection criteria that are compared to a predetermined threshold level.

Abstract: An apparatus and method for detecting the polarization of signals reflected from targets immersed in clutter. Signals reflected from targets illuminated with quasimonochromatic electromagnetic signals such as FMCW radar are received by antennas responsive to orthogonally polarized components of the reflected signals. These received orthogonal signal components are then analyzed in a processor which detects the polarization of the reflected signal by estimating the Stokes parameters for the reflected signal. The estimated Stokes parameters may then be used to generate detection criteria that are compared to a predetermined threshold level. The presence of the target is indicated when the detection criteria level exceeds the level of the predetermined threshold.

Abstract: 1.

Abstract: A terrain mapping radar utilizes two sets of separately processed radar signals, each provided by a coherent pulse doppler synthetic aperture signal processing channel connected to and for processing the signals received from a selected one of a pair of vertically displaced antennas of the type utilized in phase interferometer radars. The invention provides depression angle, and therefore elevation information from the processed signals on a cell by cell basis, uniquely, for each range/doppler cell of each of the processing channels. The invention eliminates azimuthal errors which result from the ambiguity of the range/doppler annulus, and provides a useful map metric: elevation.

Abstract: A doppler type speed sensor produces a doppler signal having a spectrum of frequencies including a frequency of peak amplitude corresponding to the actual speed of an object. The frequencies are supplied to a narrowband voltage tunable filter, the frequency bandwidth of which is continuously adjusted by a periodically reoccurring sweep signal applied thereto. The output of the filter is coupled to a peak detecting circuit which produces a pulse when the maximum amplitude signal is received thereat. The sweep signal and pulse are applied to the inputs of a sample-and-hold circuit to cause the sample-and-hold circuit to hold and produce a signal corresponding to the value of the peak frequency and therefore the speed of the object.

Abstract: In an MTI radar receiver, a clutter suppressor (46, 47, 48) is switched (72), under the control of a discriminating device (71) responsive either to the shape parameter .eta. of the Weibull distribution or an average level of a clutter suppressed signal, to be selectively operable as a Weibull and a Rayleigh clutter suppressor for best possible LOG/CFAR processing with simple cell averaging circuitry. The suppressor may comprise a first processor (61) combined with an .eta. parameter calculator (48) for converting the Weibull clutter to the Rayleigh clutter, a second processor (89) for timing, and a simple suppressor (62) for the Rayleigh clutter. (FIG. 6).

Abstract: In a color television receiver, field rate sawtooth current waves are supplied to vertical deflection windings by a vertical deflection output amplifier. The series combination of a deflection current sampling resistor and a DC blocking capacitor, coupled between the low potential terminal of the vertical deflection windings and a point of reference potential, is traversed by the field rate sawtooth current waves. The voltage across the series combination, comprising the sum of a field rate sawtooth voltage component and a field rate parabolic voltage component, is used as the drive voltage for the input winding of a saturable reactor effecting side pincushion distortion correction. The deflection current representative voltage developed by the sampling resistor is also utilized for a linearizing feedback purpose. The capacitor also serves a filtering function for the energizing potential supplied to the output amplifier.

Abstract: A clutter filter which reduces by (N-1) the number of input pulses required or operation of an N-pulse MTI canceler when L>N consecutive filtered outputs are desired. The clutter filter includes the two channels of an N-pulse MTI canceler which weight and sum the in-phase and quadrature-phase components of N radar returns, and a pair of delay circuits which introduce a delay of N interpulse time periods to the N and subsequent in-phase and quadrature-phase components of the radar returns. The stored outputs of the two channels of the canceler and the consecutive outputs of the delay circuits are combined in a complex multiplier to generate the consecutive in-phase and quadrature-phase outputs of the filter. The clutter filter has utility in a multiple-stage filter system employing a Doppler filter as the last stage.

Abstract: A variable aperture direction finding system which uses a circular array of vertical receiving antennas connected to a capacitive type goniometer located in the center of the array to receive signals from radio frequency transmission sources. The goniometer has a stator plate for each antenna and a number of rotor plates which allow for the provision of selecting suitable apertures and antenna combinations to form Lobe or Split-lobe directional patterns. The goniometer's rotation is controlled by a servo drive system which provides for both manual positioning as well as automatic operation from a remote control unit.The system utilizes a remote control panel to allow selection of either manual or automatic rotation, azimuth indication, aperture and pattern selection, and manual positioning of the goniometer.An azimuth indicator system is driven in synchronization with the goniometer.

Abstract: In a weather radar system wherein echo signals are linear-detected from the waves received at the radar, each one of echo signals being compared with the later one to derive AC component, and the mean power of the weather echo estimated from the power of the AC component, the linear-detected echo signals are amplitude suppressed before compared. The amplitude suppression effectively removes the errors due to the fluctuation of ground clutter, and the variation of AC power of weather echo due to the existence of ground clutter. An amplitude suppressor is used which has an amplitude suppressing property expressed by Y=X.sup.k, where X is an amplitude of the input signal, Y is an amplitude of the output signal, and k is a constant (0<k<1). The value of k is advantageously 0.3-0.9, and, more advantageously 0.6-0.7. If the echo signals are obtained in a form of a logarithmic signal, an amplitude suppressor which has an input-output characteristic expressed by, for example, Y=10.sup.

Abstract: A circular multimode antenna array having N radiating elements, an NXN Butler matrix and N-1 phase shifters includes feed networks comprising a back fill-in network, a sum pattern power divider network, a difference pattern power divider network and a sum-difference combiner network. The various networks are used either alone or in simultaneous combination to provide sum and difference circular antenna patterns having omnidirectional side lobes.

Abstract: A deflection coil driver includes a current driver stage comprising three power transistors, a first power transistor being caused to turn on via a class B transistor stage when an input signal of a first polarity is input to the class B stage, second and third power transistors being caused to turn on via said class B stage when the input signal has an opposite polarity. When turned on, the first power transistor couples current from a positive voltage source to the deflection coil, the second power transistor couples current from a negative voltage source to said coil, and the third power transistor couples said coil to ground. A transistor switch determines whether the second or the third power transistor is on, as a function of the voltage across the deflection coil. The current through the coil is also sensed and provides negative feedback to an input amplifier to ensure that the shape of such current matches the shape of the input signal.

Abstract: From an antenna array of a plurality of fixed, narrow beamwidth antennas, geographically oriented to provide omnidirectional coverage, first and second sets of antennas are selected in sequence. The first selected set includes several pairs of oppositely oriented antennas. The signals received by the antennas in each pair of the first selected set are combined and each of the combined signals is connected to a different one of a number of matched receiver channels. If the logarithmic video output signals from the receiver channels meet certain rules of acceptance, the monopulse ratio, formed by subtracting the outputs of the channels receiving the strongest and next strongest signals, is digitized and stored. This ratio represents the angular difference between the direction of the received signal and the direction of one of the antennas in the pair of the first set generating the strongest signal.

Abstract: An array antenna capable of simultaneously radiating several microwave parns wherein the antenna elements are individually energized by p-n junction devices that are controlled by electron beams.

Abstract: A false Doppler shift is imparted on a received signal for confusing or dupting the effective functioning of enemy fire control or target tracking signals. A radar repeater having a pair of antennae with associated amplifiers has both antennae visible to a remote radar. A frequency changer is interposed between the antennae for creating a shift in frequency that is to be returned to the enemy. The frequency changer can be either of the mechanical or electronic variety. A mechanical version utilizes a rotary probe driven by a reversible variable speed drive. An electronic version utilizes a sequence of electronic gates controlled by an electronic logic device under the control of a master oscillator.

Abstract: A line scanning or horizontal deflection circuit for a television receiver including a first scanning thyristor controlled by means of a commutating circuit comprising a second thyristor an inductance and a capacitive circuit, fed from a source which is connected to the scanning circuit by means of a further inductance. According to the invention, the gating signal of the first thyristor is derived from the signal available between the inductance and the capacitive network being taken at an output of the line.

Abstract: A circuit within a cathode-ray tube electromagnetic deflection system for correcting side pincushion distortion and regulating picture width independent of changes in the video line rate. The circuit employs a predistorted AC reference signal and a second DC reference signal in a closed-loop manner to cause a deflection current to describe precisely an ideal waveform defining simultaneously both pincushion correction and picture width regulation.