Abstract: A circuit arrangement for providing a saw-tooth current, with trace and retrace (flyback) intervals, in a deflection coil, in which the amplitude of said current is affected by modulation signal, the arrangement comprising in addition to the said deflection coil, a first retrace capacitor and a first trace capacitor which, together with the deflection coil, form a first oscillating circuit during the retrace interval, a second inductance coil, a second retrace capacitor and a second trace capacitor which form a second oscillating circuit during the retrace interval, a controllable switch connected to a power supply source through a third inductance coil and having a control electrode, connected to a periodic signal source for making the controllable switch conductive during a second part of the trace interval, and a first diode and a second diode, connected in parallel with the first and second retrace capacitors, respectively, the polarity of the diodes being such that they are made conductive by current flo

Abstract: An arrangement for providing an inflatable cover or structure having radar-energy absorbing characteristics. Thus, a structure may be either formed of, or covered by, this material -- which may be compacted during certain stages of its life, and inflated at other times in order to provide the desired radar-energy absorption.

Abstract: The repetition frequency tracking apparatus utilizes the input signal to start a timer to provide the correct phase. When the timer sweeps through the right frequency, the tracker will lock to a single pulse train within a two octave frequency spectrum. After the lockup, the tracker is switched to a free running mode to provide pseudo synchronous running through durations of missing input pulses. Accurate tracking is provided by the use of an early late gate phase discriminator for phase sensing and correcting to zero, errors at all locking frequencies.

Abstract: Frequency agility may be added to fire control radars by replacing the conventional receiver-protector/stationary-filter combination located between the duplexing circulator and the receiver input with a passive high power ferrite limiter and YIG tracking filter combination.

Abstract: A clutter discriminating fuze apparatus for preventing prefires and duds which may result through the use of electronic countermeasure techniques by the enemy.

Abstract: 1.

Abstract: An air traffic control transponder includes a synchronous digital delay line decoder for providing mode selection signals in response to pulse space coded transmissions from the ground station. The decoder comprises a shift register delay line having a plurality of delay taps along which a first received pulse is shifted. A continuously running high frequency clock pulse generator via a frequency divider provides the shifting clock to the delay line. The first received pulse synchronizes the shifting clock via the frequency divider. A plurality of monostable multivibrators connected to selected taps of the delay line provide pulse detection windows in response to the first received pulse being shifted through the stages of the shift register to which the window generating monostable multivibrators are connected. The outputs from the window generators are applied as inputs to respective pulse coincidence detection devices, the second inputs thereof being connected to receive the incoming pulses.

Abstract: To simulate the radar return from terrain of particular generic type (e.g. desert, forest, cultivated land) it is a known suggestion to employ closed-loop shift register with feedback suitable to produce particular "texture" of return from specified terrain. It is here disclosed to synchronize output of such register with azimuthal position of simulated search radar; but this alone gives "grainy" effect because "smeary" or slowly changing amplitude with range in PPI sweep is not matched by corresponding lateral, or azimuthal, "smear". This objectionable effect is overcome by providing three sets of output terminals on feedback register, giving outputs corresponding to shifts for azimuths N, N+1, and N+2. By buffing together the three outputs, an azimuthal variation at a slow rate, comparable with the variation with range, is obtained, giving a more deceptive (and thus better) simulation.

Abstract: In-phase sum and difference signals and quadrature sum and difference signals from a monopulse radar system are processed to form the sum of the in-phase signals, the sum of the quadrature signals, the difference of the in-phase signals, and the difference of the quadrature signals. The processed sum signals and the processed difference signals are then combined to form complex signals one of which is advanced and the other retarded by pedetermined time. The complex signals are then divided into sequences of frequencies of identical banks of narrow band filters. The differences between the outputs of corresponding filters from each bank are smoothed by low pass filters, averaged and then divided by a constant to form a beam pointing error value.

Abstract: In-phase sum and difference signals and quadrature sum and difference signals from a monopulse radar system are processed to form the sum of the in-phase signals, the sum of the quadrature signals, the difference of the in-phase signals, and the difference of the quadrature signals. The processed sum signals and the processed difference signals are then combined to form complex signals one of which is advanced and the other retarded by predetermined time. The complex signals are then divided into sequences of frequencies by identical banks of narrow band filters. The differences between the outputs of corresponding filters from each bank are averaged and then divided by a constant to form a beam pointing error value.

Abstract: A counter is provided for detecting the frequency of generation of collision imminence signals produced in a conventional type of anti-collision radar system for a vehicle. An odometer and/or a clock pulse generator is connected to the counter for applying a reference counting period so that the counter is utilized for generating a signal with which an alerting device which is independent from that of the radar system, is energized when the frequency reaches a predetermined value during the reference counting period.

Abstract: A dielectric aerial is disposed in contact with a dielectric liquid, and projects microwave radiation thereinto. The reflected radiation is received by the aerial, and the flow rate of the liquid given by the Doppler frequency shift between the projected and the reflected radiation. A control circuit is arranged to vary the flow rate in response to the Doppler signal.

Abstract: A code generation and receiving system for a large bandwidth Doppler tolerant signal for use by communication and radar systems includes a set of delay lines for producing discrete phase shifts on a carrier signal. One delay line with relatively large delays between taps thereon produces a set of quadratic phase shifts approximating a frequency sweep. A second delay line with relatively small delays between taps thereon produces a binary phase code.

Abstract: A system for measuring, in conjunction with a GCA radar, the crab angle of n aircraft which is making its landing approach above a runway just prior to touch-down. Two doppler radars are placed, one on each side of the runway at equal spacings from the center line of the runway, with their antennas facing each other. The doppler radars function at very nearly the same frequency. The average doppler frequency of the echo received by each radar is determined and the frequencies are subtracted from each other. The difference in doppler frequency and the ground velocity of the aircraft are coupled to a computer which solves an equation to provide the value of the crab angle of the aircraft.The result can be radioed to the aircraft so that an adjustment in yaw can be made to zero the crab angle before touch-down.

Abstract: A method for identifying radar targets, especially ships at sea involves transmitting a first interrogation pulse, thereby causing a responder to generate a first identification signal containing a first set of data concerning the identity of the target, transmitting a second interrogation pulse causing the responder to generate a second identification signal containing a second set of data concerning the identity of the target and thereafter combining the two sets of data. The method reduces bandwidth requirements and garbling. An interrogator and responder for use in the method are also provided.

Abstract: In a system for generating a synthetic aperture, a lens or antenna for focusing the radiation from an object scene onto an image sensor which is shifted by a clock at the rate of motion of objects in the object scene and thereby to produce the real tire imaging of the object scene with high resolution. A system for reconnaissance, surveillance and ground mapping. A system for high speed data imaging, medical patient scanning, label scanning, and image correlation.

Abstract: A four-port dual mode microwave mixer which operates without IF or RF switches and which provides both a passive mode of operation wherein the mixer operates as a lossy frequency translator when driven by a offset signal generator, and an active mode of operation wherein the mixer is used to convert a modulated received signal to an intermediate frequency which is mixed with the offset signal in a phase detector to detect the modulation which is used through a phase-locked loop to slave the local oscillator for retransmission of a translated signal with gain.

Abstract: A deflection circuit coupled to a deflection winding produces scanning current in the winding. A deflection rate voltage is developed at a first terminal of the deflection circuit. A source of operating voltage supplies energy to the deflection circuit, and a sensing circuit coupled to a source of voltage representative of an energy level in the deflection circuit produces an error signal for a control circuit that provides first and second control signals. A controllable switch coupled to the source of operating voltage and the first terminal provides operating current to the deflection circuit through the controllable switch. A first portion of the deflection rate voltage, under normal conditions, commutates off the controllable switch.

Abstract: High accuracy distance measurements are achieved with a low accuracy Tacan set by utilizing signals available within the Tacan set at a point of sufficient accuracy to provide accurate distance measurements to be made and thus upgrade an en-route navigation aid to higher accuracy for use in a precision landing system.

Abstract: A pulse compression coherent radar for obtaining target information is described wherein a pulse compression waveform having a predetermined bandwidth is gated at a frequency greater than the predetermined bandwidth to form a sequence of spaced apart pulses which are transmitted towards a target. A sequence of target reflected pulses are received during predetermined time intervals. The target reflected pulses of the sequence are compressed and then filtered to extract predetermined frequency components of the compressed signal. Alternatively, the target reflected pulses of the sequence are first filtered to extract predetermined frequency components and then compressed. In either embodiment, the output signal contains target doppler frequency and phase, range, and amplitude signature information. The gated pulse compression waveform may be for example a chirp or linear FM signal, phase coded signal, or pseudo noise coded signal.