Abstract: A method for determining doppler frequency by the measurement of the maxi pulse-to-pulse difference over one doppler cycle. A box-carred (sample-and-hold) phase detector's output is differentiated to obtain pulses whose amplitude represents the amplitude of individual boxcar transitions. The largest pulse amplitude is selected for indication of doppler frequency.

Abstract: The signal received through the fixed nonscanning transmitting lobe of the antenna in LORO conically scanning radar systems is demodulated to derive the interfering amplitude modulation. This modulation is then used to apply an amplitude modulation to the signal received through the scanning lobe that is equal and opposite in phase to the interfering modulation, thereby cancelling the interfering modulation and leaving only the modulation due to the conical scanning. Applications to both mechanically and electrically scanned systems are described.

Abstract: A complete frame of radar data is stored in radar real time addressed in accordance with antenna azimuth. The PPI rotating display scan is generated by deflecting the beam along the azimuth sweeps thereof under control of X-rate and Y-rate signals provided for each sweep. The X-rate and Y-rate signals are applied sequentially to X and Y binary rate multipliers which generate clock signals at a frequency proportional to the rate signals. The clock signals are applied to X and Y position counters respectively for generating the X and Y deflection signals via digital-to-analog converters. Sequential application of the X and Y rate signals to the X and Y rate multipliers generates the rotating scan. The radar data stored in memory is accessed in accordance with the azimuth address in synchronism with the generation of the azimuth display sweeps. The stored data provides the video signal for the display tube so as to generate the radar display. The rotating scan is generated in non-real radar time at a rapid rate.

Abstract: A drive circuit for an electrostatic deflection type cathode-ray tube where the drive circuit includes an amplifier and a load. At least one diode is connected between the output of the amplifier and the load and at least one push-pull emitter follower circuit is provided, the bases of whose transistors are connected to opposite terminals of the diode, the cathode-ray tube being deflected by the output of the push-pull emitter follower circuit.

Abstract: Apparatus for detecting radar echo signals with a high degree of certainty in the presence of noise. A predetermined number of consecutive, constantly changing invervals are produced having a length equal to the radar pulse width. The resolution of the system is a function of the number of signal positions chosen for examination within each interval. A secondary signal is produced for each signal position and these secondary signals are summed over preselected resolution intervals. A weighting arrangement is provided which weights the individual secondary signals inversely with their distance from the central resolution interval of the set.

Abstract: A horizontal deflection winding forms a resonant retrace circuit with two series coupled retrace capacitors during a retrace interval. A controllable circuit in shunt with the second capacitor bypasses a controlled amount of retrace current from that capacitor thereby controlling the retrace pulse width. East-west raster correction, width control and pulse amplitude control are possible depending on the variables selected for control.

Abstract: Information about air turbulence and wind shear can be obtained by analyzing the fluctuation of the envelope, at the detector output of a pulse radar, of backscatter from hydrometeors which trace the wind field. Further, under some conditions, radar returns can be identified as being backscatter from weather targets or from the ground or sea. The detector output signal is quantized into one of several class intervals whose boundaries, in mid-range, are in the same ratio. Consecutive radar returns from scatterers at the same nominal range and scan angle are quantized into either the same or different class intervals. The ratio of the number of consecutive quantizations that are different to the number of trials is a measure of the variance of relative velocities at that range and scan angle.

Abstract: A moving target indication radar (MTI) having a high azimuthal position detection accuracy. The received radar return signal is separated into quadrature components which are each converted to a series of digital samples. A continuous discrete fast Fourier transform is then performed on groups of samples corresponding to a predetermined number of contiguous azimuthal units of identical range producing an equal number of output Doppler frequency components which represent the relative speeds of stationary and moving objects within the contiguous azimuthal units. A new separate transform operation is performed for each new sample received. The transform outputs are processed to separately detect the stationary and moving objects.

Abstract: To improve the accuracy of angular measurements in a radar system by suppressing noise due to target glint, an angular-deviation signal .epsilon. derived from the output signals .SIGMA. and .DELTA. of a sum channel and a difference channel is gated so as to be read only when the sum signal .SIGMA. is at or near a maximum. In a more elaborate embodiment, passage of the deviation signal .epsilon. is also blocked when a quadrature-deviation signal .epsilon.q, likewise derived from the sum and difference signals .SIGMA. and .DELTA., has an absolute magnitude above a preferably adjustable threshold.

Abstract: A synchronous switched vertical deflection (SSVD) circuit is coupled by a flyback transformer to a horizontal deflection circuit. The SSVD circuit loads the horizontal deflection circuit at a vertical parabolic rate providing East-West pincushion correction. Because of the inductance of the vertical deflection winding, the parabolic loading is asymmetrical, producing a keystone-like raster distortion. A correction circuit, such as a constant current source coupled to the vertical deflection winding, substantially reduces the asymmetry of the loading thereby substantially reducing the keystone-like distortion.

Abstract: 1. An FM doppler fuze system comprising means for transmitting a signal hng a carrier frequency modulated by a band of random noise, means for mixing the transmitted signal with a return echo signal modified by the doppler effect of the relative movement between the fuze and a target, and means for deriving an output adapted to actuate the fuze from the low frequency doppler portion of the output from said mixing means.

Abstract: A range-gated radar system which includes a phase modulator that modulates n r.f. generator with a signal which may be binary coded. In a preferred embodiment, the binary signal is a periodic signal of 2.sup.N -1 bits per period. Starting at some arbitrary point in the sequence, K contiguous bits are transmitted then M contiguous bits are passed over, then K more bits are transmitted, and so on. The quantities M+K and 2.sup.N -1 have no primary factors in common. The radar system may be a doppler radar system using balanced digital processing which involves separating the upper and lower sideband components of modulation that exist in the return radar signal as a result of the motion of scatterers and subtracting them.

Abstract: A system for automatically focusing a synthetic array through derivation of focus error signals which may be used such as by summing a priori data so that the synthetic array data may be optimally focused. Focus error data is derived by forming the synthetic array in three sub-array. The resultant outputs of these three sub-arrays are further processed together to extract data corresponding to the degree of total array defocus. For purposes of imagery generation, the phase and amplitudes of these three sub-array resultants are vectorially summed together and the resultant is magnitude detected to yield imagery output corresponding to the full synthetic array. For derivation of focus error data, the mean (bisector of the relative phase angle between the two end sub-array resultant vectors is measured. This derived bisector's phase angle is compared to the phase angle of the central sub-array resultant vector.

Abstract: This invention relates to pulse radar detection of targets in extended media, including natural phenomena such as oil, coal and ore deposits within the earth. In particular, this invention relates to a pulse radar system employing a synthetic pulse formed from a Fourier spectrum of frequencies generated and detected by a digitally controlled transmitter and receiver circuits.

Abstract: A vertical deflection amplifier includes a driver amplifier stage having a source of sawtooth deflection signals at the vertical rate and direct current feedback from the vertical deflection winding as inputs. The driver amplifier stage drives a pair of voltage translation stages each of which drives a transistor in a complementary-symmetry output stage. The voltage translation stages are independent of each other and are biased to operate as constant current sources with no signal present for controlling the quiescent current of the output stage. The improved vertical amplifier can thus be utilized to pass a horizontal rate signal combined with the vertical rate signal to effect image rotation when the deflection amplifier is used with an image pickup tube.

Abstract: A dual frequency moving target radar system having a lower frequency chan which provides relatively good moving target detection in the presence of such obstacles as foliage and precipitation and a higher frequency channel which provides accurate location of targets wherein the Doppler signals from the two channels are correlated to provide suitable target identification which target and clutter are present in the same resolution cell. The Doppler frequency is processed to distinguish the moving target from other returns. Electroacoustic transducers can be used in either of said channels to aid in target identification.

Abstract: A radar system of the invention transmits a series of microwave burst energy backwardly of stationary vehicle to receive a return signal. When the return signal occurs within a preset time interval, a first and second Doppler signals are derived by mixing the return signal with first and second locally generated oscillations having a phase difference therebetween so that there is a varying phase difference between the first and second Doppler signals depending upon the direction of movement of the detected vehicle. A phase discrimination circuit generates a warning signal when the two Doppler signals have a predetermined phase relation.

Abstract: Means for enabling a high range resolution radar to maintain precise range nformation of a high velocity maneuvering aircraft or other target during radar operation. A voltage indicative of target motion is provided as an input to a voltage controlled oscillator that develops a waveform having a frequency that varies from the frequency of a stable reference oscillator by an amount commensurate with that voltage input. The frequency differential of the two oscillators is utilized to cause the tracking window to move in proportion to the range rate of the target.

Abstract: A spot killer circuit wherein when a power switch is turned off, a transistor interconnected between the first gird of a picture tube and a low voltage supply is driven into the cut-off region so that the first grid voltage may be abruptly raised so as to cause the discharge of the picture tube.

Abstract: An attachment is provided for aircraft, and particularly for helicopters, for use in conjunction with a microwave interference pattern sensor (MIPS) system, to sense low velocities, for example, such as are encountered when the helicopter is in a hover mode. The attachment includes an antenna array which is separated from the MIPS antenna array, and which comprises two sets of transmitting and two pairs of receiving antenna horn apertures mounted in orthogonal relationship with one another, the transmitting apertures of each set being scanned in sequence to produce a moving energy pattern which is intercepted by the receiving antenna apertures of the attachment, even though the aircraft is stationary.