Abstract: In a microwave lens antenna of the parallel plate type for scanning a beam wherein a plurality of feed probes spaced along the focal arc are simultaneously excited in groups in accordance with weighting functions, the phases of the feed probes are optimized by predetermination of the lengths of the coaxial cables supplying energy to the feed probes.

Abstract: A linear driving circuit includes a full bridge drive circuit across which a d.c. motor is connected. Each side of the bridge circuit is controlled by an associated complementary transistor loop, each of which is in turn controlled by an associated control operational amplifier. Each control operational amplifier is referred at one-half the voltage across the bridge circuit by a common voltage divider. The currents through each half of the bridge circuit are compared to provide current feedback.

Abstract: An integrated airport terminal area surveillance system, including a plurality of spaced apart interrogating and receiving stations and central equipment for controlling the stations operates in search and track modes by transmitting interrogation messages and receiving resulting replies. In the search mode the stations interrogate by directional beams all aircraft operating within the entire terminal area and enrolling the position and identification of replying aircraft into a system memory. In the track mode those aircraft enrolled in the system memory are individually interrogated. A system map is divided into memory cells corresponding to predetermined geographical cells. The means by which an aircraft is interrogated is determined by the geographical cell in which the aircraft is located.

Abstract: A multi-mode radar includes a local oscillator referenced to the radar magnetron and includes logic provided to side step the local oscillator during the latter portion of the radar interpulse period so as to permit adjustment of the receiver gain during this period without interference from distant targets. In addition, IF amplifiers are selectable in accordance with the operational radar mode selected.

Abstract: A broadband concentric power combiner or divider for use with microwave frequency signals is in the form of a multi-section folded transmission line. The folded transmission line is comprised of a plurality of concentric cylinders wherein the outer conductor of one section comprises the inner conductor of an adjacent section, the various cylinders being the various conductors.

Abstract: A phase detector which employs four memory elements suitably comprised by D-type flip-flops. The detector provides an output dependent upon the phase difference between two input signals. One pair of memory elements is clocked by one input signal. The other pair of memory elements is clocked by the other input signal. The memory elements are so arranged that when the ratio of the frequencies of the input signals is less than 2:1, the detector provides three output states which may be used in a phase locked oscillator to cause, in the first state, an increase in the frequency of one input signal; in the second state, no frequency change; and in the third state, a decrease in frequency. Above a frequency ratio of 2:1, the detector never enters the second state. Elimination of the second state under such conditions decreases the time required for a phase locked oscillator with this detector to achieve phase lock.

Abstract: A beam scanning through a receiver is detected at the receiver deriving a threshold level from the peak of the received beam, the threshold being used to detect the received beam envelope as delayed by an analog delay circuit.

Abstract: In a radar display system wherein radar return signals are received at a first rate and displayed at a second, usually higher rate, each radar return signal is digitized and used to update a main memory comprised of a random access memory so that the main memory contains information related to a plurality of radar return signals arranged therein in a logical order. The main memory information is continuously clocked out for display by an address counter which counts through two complete cycles in a first stage before incrementing a second stage so that the stored information related to each radar return signal is read out for display twice consecutively before the stored information related to the next radar return signal is read out for display.

Abstract: A high speed a.c. voltage regulator comprises a transformer having a plurality of switchable primary windings across which an unregulated voltage is impressed and which control the regulated voltage, and a secondary winding across which the regulated voltage is generated. During a regulation period, which comprises one cycle of the unregulated voltage frequency, peak unregulated input voltage is compared against an upward ramping reference voltage to control a source of clock pulses, where the instantaneous level of the reference voltage is related to the number of clock pulses generated during a regulation period. The number of clock pulses generated during a regulation period controls the switchable windings.

Abstract: A thermomechanical vacuum regulator adapted for use in automatic temperature control systems includes a bimetal strip which flexes in accordance with the temperature of air stream whose temperature is to be controlled. The bimetal strip positions a whiffle tree beam which carries a vacuum valve for communicating a source of vacuum with a chamber within which vacuum is regulated, and a vent valve for communicating the chamber with a source of ambient air. The vent valve seat is located on a floating diaphragm which forms one wall of the chamber. In alternative embodiments, one of the valves is replaced by an orifice and column.

Abstract: An antenna and scanning means therefor particularly useful in an aircraft landing system operating in the microwave frequency range. The antenna is of the line phased array type which includes digitally controlled phase shifters for each of the radiating elements of the array. The beam formed by the antenna is steered by incrementing the phase shift applied at each of the array radiating elements by an amount of phase which is dependent in part upon the position of the radiating element in the array. Phase increments sufficient to shift the beam position by one coarse step (0.1.degree.) are applied to symmetrically located radiating element pairs, pair by pair, until all elements have been incremented. The beam is thereby caused to move through one coarse step in a number of fine steps equaling the number of pairs of elements in the array. An additional feature of the scanning means is the application of phase increment to the array elements in a pseudo-random sequence.

Abstract: A pressure responsive diaphragm is attached to a substrate carrying a thick film metallic coating covered by a dielectric glass coating so that the diaphragm and thick film coating comprise a pressure variable capacitor. Changes in pressure difference across the diaphragm force the diaphragm to roll against the glass to vary the area of diaphragm in contact with the glass, thus changing the capacity.

Abstract: A command driving mechanism for command bars which are rotatable about the longitudinal axis of and transversely displaceable with respect to the horizontal reference line of a flight director indicator includes a command plate, the plane of which is parallel to the front face of the indicator. The perpendicular axis of the command plate is coaxial with the longitudinal axis of the indicator and rotatable thereon in accordance with roll commands. Command bar struts are pivotally supported at diametrically opposed peripheral portions of the command plate and connected through a wire bail which is driven by a helical cam in accordance with pitch commands.

Abstract: A phase lock detector for a digital frequency synthesizer. The frequency synthesizer includes a programmable digital frequency divider for the output signal, a reference frequency Fr oscillator and a phase lock loop which controls the frequency of the synthesizer output by comparing the phase of the frequency divider signal with the phase of the reference signal. The frequency Fr of the synthesizer is determined by programming N in the relationship ##EQU1## The phase lock detector includes logic means providing a "window" which is "open" for a count which is symmetrically less than and more than the factor M. The detector does not signal "out-of-lock" condition as long as output from the programmable divider occurs during the time the detector window is open.

Abstract: A mono-lobed scanner used in a direction finding radar receiver has an antenna in the form of a parabolic dish having four parallel dipole antenna elements which are located physically about the parabola focal point. The outputs of the dipole elements are combined to produce a sum signal, a delta elevation signal and a delta azimuth signal. Pointing or positional inaccuracy of the antenna caused by cross polarization products is corrected by manipulation of metalic rods located about the dipoles and in relatively close proximity thereto.

Abstract: A digital frequency synthesizer includes an oscillator and a variable frequency digital divider, whose divisor N is switchably selected for dividing the oscillator frequency. A counter accumulates a count related to the number of cycles of the divided oscillator frequency occurring in a unit time, with this number being used to set the divisor of a second digital frequency divider. The oscillator frequency is also divided by the second divider, with the resultant signal having a frequency of N Hz.

Abstract: A readily portable ultraviolet radiation monitor includes an ultraviolet radiation sensitive cell or transducer arranged in an electrical circuit to drive a digital voltmeter. The ultraviolet sensitive transducer includes a solar blind vacuum photodiode which is exposed to the area of interest through various ultraviolet filters to produce a desired predetermined transducer response characteristic. The monitor is generally T-shaped with the transducer located to view out of one arm of the T, while the meter display is viewed into the other arm. A dependent handle comprises the leg of the T.

Abstract: A power amplifier includes a plurality of generally identical amplifier elements connected in parallel between input and output transmission lines for phase coherent addition of the signal outputs of each amplifier element. Resistive elements are connected across normally phase identical points on the transmission lines. If the amplifier becomes electrically unbalanced, power is absorbed in the resistive elements, thus protecting the amplifier elements.

Abstract: A radar return signal is analyzed by amplitude comparators so as to classify the radar return signal with respect to 2.sup.n -1 threshold levels to thus produce n parallel bits for each classification defining the instantaneous amplitude of the radar return signal. The bits in a given significant bit position (most significant, least significant, etc.) comprise a word which moves through the video storage device serially with respect to bits in the same significant bit position and in parallel with respect to bits in the word comprised of different significance bits. Input buffers in the form of n storage registers are provided, each storage register being associated with a particular bit significance. The bits are entered into their associated storage register at a rate dependent upon the desired radar range. The bits are optionally integrated on a bit-by-bit basis and then entered into a main memory having n circulating storage registers arranged in parallel.

Abstract: A switching transistor connects an input terminal at which a wide range of voltage levels may be impressed with an output terminal at which a relatively constant voltage is desired. A charge storage circuit whose discharge frequency is controlled in accordance with the output voltage and discharges a further charge storage circuit operating in accordance with the input voltage level. The further charge storage circuit controls the ON-OFF state of the switching means. Switching transistor turn off transient energy is inductively coupled to the output terminal.