Abstract: A constant false alarm rate video processor which uses a tapped delay line operating as a "sliding range window" to provide tap outputs corresponding to the center of the delay line and a predetermined number of discrete range cells on either side thereof. A "least of" circuit is responsive to all taps except the center tap of the delay line and the mininum signal extant on these taps is outputted and substracted (in scale factored form) from the signal of the delay line. The circuit thereby adaptively excludes target and ground clutter bias in providing the CFAR (normalized) signal output of the combination. An additional circuit arrangement is shown for digitally mapping the "least of" signal values over a predetermined threshold. The digital map output converted to analog then provides the scaled "least of" signal to be subtracted from the central range cell and for controlling the threshold of response of the mapper.

Abstract: A radar reconnaissance system for recognition of echo signals from track type vehicles such as tanks. Circuits are included for identifying a Doppler spectrum shift on either side of the spectral line 2FD (harmonic of the main moving target Doppler frequency) due to echo signals from a track of the vehicle, the tracks inherently having point-by-point velocities up to double the vehicle velocity.

Abstract: A dual-pulse coherent MTI system having a time interval between pulses as short as zero. The pulses are "chirped" in opposite sense, the latter constituting a unique coding for eliminating range ambiguity problems. Video return signals are received and applied to two parallel channels each containing pulse compression and limiting circuits. The pulse compression circuits are matched uniquely to the positive chirp slope pulse in one channel and to the negative chirp slope pulse in the other channel. The channel corresponding to the earlier of the two pulses is subjected to a fixed delay of one pulse width before the outputs of the channels are differenced to produce a net MTI signal. This is a continuation of application Ser. No. 159,751, filed July 6, 1971, now abandoned.

Abstract: A coherence reference signal device, and utilizing radar system therefor, in which a coherent reference signal is provided for phase detection of target echo signals for subsequent application to a canceller or other signal processor. The device recognizes the phase conditions throughout a given transmitted pulse (range bin) and provides this same phase information repetitively for each of n range bins of interest. A tapped sonic delay line of metallic glass material with input and output transducers and a summer circuit provide the coherent reference signal produced to a phase detector which also receives the echo signals, preferably both in the IF frequency domain.

Abstract: A pulsed radio-frequency transmitter-modulator system including circuits for converting a sample of the transmitter-radio frequency pulse to a corresponding video pulse and comparing this to the standardized timing pulse of the system to develop a control signal as a function of the leading edge delay and pulse duration of the RF pulse compared to the system timing pulse. The control signal is applied in a type of feedback loop including circuits responsive thereto for adjusting the pulse position and duration between the system timing pulse generator and the modulator of the pulse transmitter. The principal purpose is relief from the effects of temporal noise and the resulting improved performance of moving target indicator circuits associated therewith.

Abstract: A multioctave, multifunction antenna system including three planar terraces each having four symetrically placed individual turnstile arrays. A first terrace includes turnstile arrays of a first relatively large size, the second terrace is axially spaced therefrom and includes four second individual turnstile arrays of a second size smaller than the first size. A third terrace includes a similar arrangement of four individual turnstile arrays of a third and smallest size. A ground plane for the arrays of the second and third terraces is included in the plane of the next larger arrays, the first terrace having a spaced ground plane in a separate plane. Between the planes of each terrace an absorbing material provides a lossy medium for broadbanding and reduction of the interaction among the arrays of any given terrace with those of the other terraces.

Abstract: Apparatus for improving the life of metallic bellows used in a hermetically sealed device having a movable element therein such as, vacuum relays and circuit breakers. The convolutions of the metal bellows are filled by a silicone dielectric gel for an axial length including several such convolutions adjacent to the movable end of the bellows, thereby to damp axial mechanical vibrations and prevent excessive stress build-up in the bellows portions adjacent to the moveable end.

Abstract: An FM-CW vehicular distance and relative speed measuring device which compares instantaneous reflection signal frequency to the instantaneous FM-CW transmitted frequency to derive distance (range) and speed information. Searching means including a mixer, frequency programmer, and logic circuits evaluates a plurality of fractional range increments for signal presence and Doppler spectrum evaluation to determine relative velocity with sense. The FM-CW waveform is a sawtooth and means are included for blanking the sawtooth flyback.

Abstract: A pipe cutting machine having a pair of driven rollers and a free wheeling cutter wheel with novel means for advancing the cutter radially into the work. A single column with rack and key adjustment arrangement accommodates different pipe diameters rapidly. The cutter advancing hand lever operates with an eccentric for large mechanical advantage. Unique hole, keyway and split-ring clamping means are included for properly aligning the cutter wheel axis parallel to the drive roller axes at any predetermined column height. The rollers are both driven from an all spur (or parallel shaft helical) gear arrangement and are supported from a cantilevered spindle and bearing arrangement.

Abstract: A 180.degree. microwave phase-bit device implemented in a stripline medium with integral transitional coupling into a waveguide by means of an H plane loop within the waveguide. The device is particularly well suited for use in digital diode phase shifters attached to waveguide feed networks, such as in the case of corporate feed of plural antenna elements within a phased array. The device is shown both independently and in connection with diode phase shifters providing intermediate values of phase shift such as 22.degree., 45.degree. and 90.degree.. PIN type radio frequency diodes would normally be used to provide the necessary switching function.

Abstract: A hybrid AC power switching arrangement in which two ganged switch banks in series are employed along with a pair of reverse parallel (back-to-back) SCRs across each contact pair of the second switch gang. SCR control means and interlock control means are provided so that the first switch gang (closest to the power source) closes first, energizing the SCR control and permitting the SCRs to conduct load current in a corresponding phase leg, beginning at or near a zero voltage cross-over point. After all phase legs are conducting through the SCRs, the second switch gang is closed bypassing the SCRs. On circuit break, the second switch gang (i.e., the one closest to the load) is opened first, the load current diverting immediately through the SCRs for another interim period until the SCRs in each individual phase leg are extinguished as the instantaneous current in the corresponding phase lead passes through or near zero.

Abstract: A fiber optic delay line-controlled oscillator or tuned amplifier. Two embodiments are shown and described, one employing a single solid state active element and the other employing two such elements. The fiber optic delay line or lines employed are combined electronic-to-light transducer(s) supplying the delay line or lines and optical-to-electronic transducer(s) responsive to the optical delay line or lines output(s). That combination provides the tuned or oscillatory feedback path. In one embodiment, a plurality of delay lines are effectively switched into the circuit discretely and selectively in response to a staircase control function.

Abstract: A relay structure especially for miniature relays in which the armature part is held in place with respect to the electromagnet by means of shoulder pieces projecting within the relay housing. The housing and shoulder pieces may be made of a thermally softenable material, such as a "thermoplastic," so that the assembly may be heated and mechanically deformed to adjust clearances as a part of the final assembly process. Two versions of a flap or leaf spring for extra retention of the armature part are shown.

Abstract: A receiving arrangement for a pulse radar tracker facilitating low elevation angle tracking. The received signals are sampled along the focal plane of the receiving antenna system aperture. Range gating at IF and delay line serialization are provided to generate a simulated (synthetic) scan of the aforementioned aperture plane in the form of a coherent signal waveform. The main lobe of a multipath (ground reflection in the elevation case) is substantially eliminated by the time gating and filtering is provided to greatly reduce the corresponding sidebands. Desired (direct) received signals are substantially unaffected.

Abstract: An oscillator or similar device employing a frequency setting SAW element having a piezoelectric substrate and an arrangement of interdigital finger transducers mounted thereon. In one embodiment, two interdigital finger transducers provide surface acoustic wave launching and reception respectively and in another embodiment, two additional transducers form a part of a discriminator circuit. Phase detection either between the electrical connections of the launching and receiving transducers or through the discriminator arrangement generates a feedback control signal which is applied across the ends of the substrate as a stress-controlling signal in a manner to compensate for temperature and other environmental factors which otherwise change the frequency of oscillation.

Abstract: A system involving a mechanically or electronically scanned beam of electromagnetic energy and separate antenna means for transmitting a phase reference signal. A remote receiving station, such as on-board an aircraft on landing approach, is able to process received signals coherently to take advantage of the increased accuracy available in such processing.

Abstract: A resettable high-voltage fusing device including a vacuum interrupter and an arrangement of magnetically displaceable rod members which are displaced by the magnetic forces resulting from overload currents flowing through them. For currents below the "blow" rating, a spring arrangement keeps the rods in place by applying axially opposing forces at the ends thereof, and the vacuum interrupter is kept closed. After rod displacement caused by overload current the vacuum interrupter opens in response to one of the springs released by displacement of the rods.

Abstract: A system primarily for industrial security; to detect intruder movement in interior areas. A Doppler detecting, bi-static system utilizing range (time-delay) areas of varying shapes. The detection containment obtained is orders of magnitude more absolute than conventional systems which depend on antenna beam shaping to obtain varying detection coverage. Range discrimination is effected by bi-phase modulating the transmitted CW radio frequency waves according to a maximal length pseudo-random code. The autocorrelation function provides the ideal range discrimination response for the application. Omni antenna coverages are provided and a lower rf band is used than in conventional systems for this use, affording lower moving clutter susceptibility and better coverage. The general pseudo-random coding techniques are available within the state of the Radar Arts.

Abstract: A received signal processor in a remote receiving (airborne) station including amplitude modulation elimination means for improving the determined value of Doppler beat, angle representing signal, generated from reception of the transmissions of a Doppler Scanning (ground) Beacon station, for enhancing the accuracy of air derived angle data in the presence of near-angle multipath signal.

Abstract: A space-fed phased-array arrangement in which the plural antenna elements each include first and second (front and rear) individual radiators. Between these input and output radiators, there is a combined controllable phase shifter and controllable electronic switching arrangement. In accordance with external control signals, the amount of phase shift (phase delay) introduced by each element may be controlled, and by appropriate programming of these phase shifts, beam formation and pointing angle may be determined. The electronic switch devices are programmable to convert any or all of the antenna elements to reflector or retro-directing elements whereby a rear-pointing beam may be generated and scanned in substantially the same way as the forward beam is generated and scanned. In the retro-directive (reflective) mode, energy from the primary feed passes bi-directionally through the reciprocal controllable phase shifter sections.