Abstract: A fluid level sensor for determining the amount of liquid in a container. Thin metal plates are placed parallely adjacent each other to form a capacitor cell coated with a non-hygroscopic film. The plates are mounted on the walls of the container containing fluid. As the fluid covers more surface area of the capacitor plates, the dielectric properties of the fluid increase the capacitance of the cell proportionally. The plates are connected to an oscillator whose output frequency varies with the change in container fluid levels. By monitoring these frequency changes, the container fluid levels of the fluid in the container can be controlled.

Abstract: An array antenna for a radar is shown in include a phase shifter arrangement wherein, in the transmitting mode, ferrite phase shifters are used to collimate and direct a beam of transmitted radio frequency energy originating at a feed horn and, in the receiving mode, amplifiers and diode phase shifters are used to amplify and to focus received radio frequency energy on a feed horn.

Abstract: A transducer adapted to couple radio frequency (R.F.) energy from a section of waveguide to a section of stripline is shown to comprise a section of stripline supporting a series of probes projecting inside the waveguide with a shaped length of a dielectric material disposed around the probes within the waveguide to match the velocity of propagation of the R.F. energy in the waveguide to the velocity of propagation in the stripline, thereby achieving tight coupling and improved directivity.

Abstract: A sprayable ablative coating formulation comprises a combination of a polymeric resin, a curing agent, cork flour and a vehicle such as toluene. The mixture is sprayable using conventional spray equipment. The surface to be coated is first sprayed with a primer to improve adhesion, and the mixture is than sprayed over the primed surface until a desired thickness is formed. Once cured, the coating has a uniform fine texture and thickness, providing thermal insulation for the coated surface. Pigments may be added to the formulation to acheive specified coloration of the coating.

Abstract: A fast and inexpensive set-on oscillator is disclosed. According to the invention, the input signal is processed in two paths. In the first path, a coarse estimate of the input frequency is made. In the second path, the input signal is down converted to a baseband. The frequency of the relatively low frequency baseband signal is measured and a new signal at this frequency is synthesized. The synthesized signal is up converted in frequency. The down-conversion process is performed ambiguously and circuitry is included to resolve the ambiguity. The up conversion process is also performed ambiguously. The coarse estimate of the input frequency is used to resolve this ambiguity.

Abstract: A method and appaatus for curing a gasket material on a cap, the apparatus having a microwave transmitter, associated wavegide and a device for moving multiple caps through the waveguide. A plastic material is applied to the cap so as to form a gasket. The cap is then moved through the waveguide where microwave energy is absorbed by plastic material. The plastic material then heats from room temperature to a predetermined curing temperature in the waveguide. The cap is then removed and allowed to cool back to room temperature so that the gasket material will harden.

Abstract: A T1 digital carrier system having a transmitter, receiver and a plurality of intermediate repeater stages. Each remote repeater has a select switch for automatically selecting that the remote repeater be placed in loop-back mode should a combination of framing bits occur in the serial bit stream that matches that said remote repeaters address therein, thereby allowing remote testing of the communications link and repeaters. In addition, no additional test lines are required to verify a T1 communications link.

Abstract: An autoregressive model simulator is disclosed. The simulator produces time multiplexed samples of a plurality of signals generated from autoregressive coefficients. The order of the autoregressive model is selected by the configuration of identical integrated circuit chips. The autoregressive coefficients for each signal and past samples of the signal are rotated through FIFOs in a manner which enables the simulator to be simply controlled.

Abstract: A stripline transition between two layers of a multilayer microwave stripline assembly. Two stripline layers are sandwiched between metal plates. The metal plates have formed therein complementary curved transition regions and force a stripline to undergo a gradual transition from a first layer to a second layer of the assembly.

Abstract: In a millimeter wave monopulse first detector array for use in seeker applications in a guided missile employing quasi-optical, or Gaussian beam, signal transmission, a first detector is shown to include a patch antenna array, a mixer and a power divider in a monolithic implementation for extraction of the monopulse information in a radar receiver.

Abstract: An air filter and particle removal system for eliminating impurities from air. The system is constructed with an upper electrode plate facing a lower electrode plate. A flypaper-like material is placed close to the lower plate with the sticky side of the material facing the upper plate. The plates have different voltage polarities so that when air is passed through the duct, charged particles within the air will move toward the lower plate and are caught by the flypaper-like material. Further, the upper plate is shaped to create turbulences in the air to cause other impurities to flow over and be caught by the flypaper-like material.

Abstract: A gasket, and method of making same, is shown to consist of a substantially solid core of silicone rubber supporting an electrically conductive coating primarily made from a polythioether impregnated with particles of nickel, the coating also containing an oxidizing inhibitor.

Abstract: A radar system adapted to operate with a selected one of a plurality of pulse repetition intervals to produce a corresponding train of transmitted pulses of radio frequency energy in response to a train of trigger pulses and to receive returns from objects in response thereto, with returns from stationary objects producing signals with the same phase shift relative to the phase of a reference signal. The system includes a switching circuit responsive to a signal representative of the selected one of the pulse repetition intervals, for producing charge controlling signals with time intervals between the charge controlling signals and the trigger pulses being selected in accordance with the selected one of the pulse repetition intervals. A pulse forming network, is provided for storing energy in response to the charge controlling signals and for providing output pulses in response to the trigger pulses.

Abstract: An ice barrier for a selective ice cube and crushed ice dispenser having a crusher section including a crusher arm mounted to a horizontal shaft axially rotatable in either direction, and a stationary crusher arm mounted to one side of the shaft. When the shaft is driven in one direction, ice pieces fed to the crusher section are caught and crushed between the rotating and stationary crusher arms. However, when the shaft is driven in the opposite direction, ice pieces escape down the side of the shaft opposite the stationary crusher arm thereby avoiding being crushed. The ice barrier is frictionally coupled for rotation with the shaft between a first position in the whole ice piece path and a second position out of the path. Accordingly, the ice barrier blocks the whole ice piece path when the crusher is operated in the ice crushing mode.

Abstract: An integrated field effect transistor capacitor structure having a capacitor connected between source and drain electrodes is described. In one embodiment, the capacitor is formed over a drain contact by providing a dielectric over said contact and an airbridge upper plate between said dielectric to the adjacent source contact. Preferably, the capacitor dielectric is the same dielectric as the FET passivation.

Abstract: A seeker having a gyroscopic spin stabilized optical arrangement adapted to gimbal relative to a body in response to a current fed to a precession coil by a processor. Gimballing action of such optical arrangement within the body is measured by a voltage induced in a cage coil. The precession coil and cage coil are mounted adjacent to each other. The seeker includes a cage coil compensator comprising a differencing network and a differentiator. Changes in the current fed to the precession coil induces unwanted voltage in the adjacent cage coil. The differentiator is fed by the current in the precession coil to produce a voltage related to the rate of change in the current in the precession coil and hence, related to the undesired voltage induced in the cage coil. The differencing network is fed by the voltage produced by the differentiator and the total voltage induced in the cage coil to subtract from such total voltage the undesired portion thereof induced therein by the adjacent precession coil.

Abstract: A distributed circuit includes a plurality of field effect transistors (FETS), each one of such FETS having gate, drain and source electrodes, with a first portion, or a first channel, of such FETS having gate electrodes and drain electrodes successively coupled between a first input terminal and a first ouput terminal, and a second like portion or a second channel of such FETS having gate electrodes and drain electrodes successively coupled between the first input terminal and a second output terminal. Separate bias circuits are provided to the input electrodes and the output electrodes of the first and second channels. Bias signals fed to the input bias circuits and coupled to the input electrodes to place the FETS in an "on" state to provide gain to r.f. input signals fed thereto, or in a "pinch-off" state to isolate r.f. signals fed to the input electrodes of the FETS. Accordingly, a 1.times.2 signal splitter or a 1.times.2 switch which provides gain to a signal is provided.

Abstract: An input command system for an electronic refrigerator control wherein dedicated function keys are provided for inputting commands to the processor. The processor will not accept inputs from the dedicated function keys unless an enable key is pressed first. The enable key is hidden on the control panel so as to avoid unauthorized inputting of commands. Once enabled, the processor receives commands for a predetermined time period that is extended when commands are input.

Abstract: A spread spectrum signal detector for sampling a modulated carrier employing a zero-crossing detection means having two independent control loops, a first loop for a zero-mean threshold control and a second loop for AGC control. An IF sampler quantizes the received spread spectrum signals at IF and provides high immunity to interference or jamming. The IF signal is sampled at a number of quarter cycle intervals to allow sampling in sequence of the in-phase (I) and quadrature-phase (Q) components. The output of the IF sampler is two bits, a sign bit and a magnitude bit. The zero-mean threshold control loop using only the sign bit of the I and Q samples sets a threshold level (T0) to detect the zero-crossings of a received waveform. Two magnitude threshold levels are set at fixed offsets from the T0 threshold level.

Abstract: A technique for etching tub structures and vias on the backside of a wafer comprised of gallium arsenide and for providing a planar surface on said backside of the gallium arsenide wafer is described. The tubs are formed by providing a layer of resist over the backside of the gallium arsenide substrate, and this layer is patterned to provide selected areas covering regions where tub structures and vias will be provided. In the selectively exposed regions, palladium and gold are sequentially deposited. The resist pattern is then stripped, and a second resist layer pattern is deposited masking portions of the continuous conductive layer and areas where vias are to be provided. The tub structures are then provided by suitably etching the tub to undercut portions of the resist and the palladium layer. A second continuous conductive coating is then provided in the tub structure to provide a plating layer for subsequent plating of a gold film over the palladium.