Abstract: A heterodyne CO.sub.2 optical Doppler radar comprising a ring type of traitter laser and twin local oscillator lasers which are automatically controlled to operate at a difference frequency equal to the intermediate frequency of the radar, which may be in the VHF band. The output of one of the twin lasers is injected into the transmitter laser for stabilization purposes and the output of the other of the twin lasers is heterodyned with the received target return signals to form the radar's intermediate frequency signal.

Abstract: An audiographic telephone conferencing system between a plurality of parties or users either directly connected or through a piece of apparatus known as a "meet me bridge" over voice grade telephone lines. Each user has a programmed personal computer which controls a programmable or "smart" modem, cassette recorder/player, and speakerphone. A protocol is implemented by the software, i.e. the computer program, in each of the computers which puts its respective modem in a listening mode to monitor the phone line at all times. The computer is further programmed and includes a memory for storing and transmitting graphics presently on hand to other user(s) via the modem during a teleconference or alternatively receive graphics from another user, or it can switch to an external graphics program to make new or modify existing graphic images.

Abstract: A rare earth permanent magnetic apparatus for the containment and control thout any substantial loss of field flux comprising electro-deposited layers of rare earth magnetic material disposed and laid up around a ferrite center core element, the first or inner layer comprising a uniformly thick supply magnet to produce the magnetic field to be controlled, and the second or cladding magnet constituting a layer of diminishing thickness from the outboard ends of the device towards and to the plane of zero magnetic potential at or near the middle of the device.

Abstract: A passive millimeter wave image guide power limiter comprising a length of ielectric transmission line or waveguide for millimeter wave frequencies located on a relatively thin conductive ground plane forming thereby an image guide and including a planar doped barrier diode structure formed in the dielectric transmission line with the planar doped barrier structure being integrally grown in a slot milled in the constituent material, i.e. gallium arsenide, of the waveguide transversely across the width dimension thereof so as to be oriented perpendicular to the flow of RF power being propagated along its length dimension. The planar doped barrier structure becomes conductive at a predetermined power level to reflect any further incident RF power back toward the power source.

Abstract: Selective etching of microelectronic devices comprising crystal substrates s achieved by electrically masking conductive areas thereon which are not to be etched by ionic bombardment. The electrical masking is accomplished by biasing the selected areas with a bias voltage which will repel the ions, which are attracted to all of the unbiased portions of the microelectronic device.

Abstract: Steerable phased array antennas of the tapered type in which the antenna ment power is maximum at the center of the array and tapers off on either side thereof. The phase shifters of each antenna element are of the binary digital type with the number of stages and hence the phase accuracy being maximum for the high power center antenna elements and tapering off on either side thereof. Redundant stages for the binary phase shifters can be provided to increase reliability.

Abstract: A phase transition detector for PSK signals which utilizes a dual channel SAW differential delay line to achieve a required delay. Each channel or path of the SAW device comprises an input and an output transducer. The two channels provide a predetermined differential delay (T) inasmuch as they are of different lengths. A PSK input signal is delivered to a power splitter, with the output therefrom coupled to the pair of input transducers of the SAW device. The output transducers are coupled to a multiplier which serves to detect phase transitions in the input PSK signal. The multiplier output is coupled to an output terminal via a low pass filter which provides harmonic repression. In another embodiment a SAW device comprises a bank of dual channel differential delay lines with each dual channel set to a different predetermined delay (T) so that a plurality of PSK signals of different chip rates can be separated out and detected.

Abstract: A magnetic cladding device having a constant exterior magnetic potential al to a magnetic potential at a point between either end of an active magnet for enhancing the active magnet's field and reducing magnetic field leakage comprising a magnetic cladding circumscribing an active magnet and having a magnetic axis transverse to that of the active magnet.

Abstract: Circuitry is disclosed for processing Doppler-shifted radar signals or ot noisy signals which fluctuate widely in frequency. The circuitry includes a dual channel discriminator including a voltage controlled oscillator as part of a feedback loop for frequency tracking of said signals. The discriminator further includes a frequency pass circuit in one channel thereof and a frequency stop circuit in the other channel thereof, with the outputs of these circuits applied to a multiplier. The multiplier output controls the frequency of the voltage controlled oscillator. The voltage controlled oscillator output is heterodyned with the input signals to obtain the heterodyned signals for application to the aforementioned two channels of the discriminator.

Abstract: A millimeter wave dual beam line scanning antenna integral with a tunable solid state oscillator is disclosed. The antenna provides two fan-shaped beams from opposite faces and when the antenna is rotated, a roughly conical shaped scan obtains. Furthermore, variation of the oscillator frequency causes a variation in radiation angle and provides two line scanning beams from opposite faces.

Abstract: A resonator having a desired frequency is made from a quartz crystal resonator plate by a method including the steps of:(A) etching the quartz crystal resonator plate to a frequency slightly higher than the desired frequency,(B) vacuum desposting metallic electrodes onto the active area of the resonator plate to lower the frequency to a frequency that very closely approaches the desired frequency, and(C) treating the plate with the deposited electrodes with UV-ozone to oxidize the electrodes in a slow, precisely controlled manner to the desired frequency.

Abstract: Acoustic signal processing apparatus for the frequency-partition processing f a wideband RF spectrum surface acoustic wave (SAW) input signal into a multiplicity of relatively narrowband individual contiguous acoustic wave output signals, utilizing a wideband, linearly-dispersive, slanted array input transducer arranged on a wave-conductive surface with multiple arrayed output transducers, each frequency-responsive to a respective band of frequencies emanated from the input transducer.

Abstract: A relatively narrow beamwidth (10.degree. or less) receiving antenna patt is formed at the receiver end of a radio frequency transmission link where a plurality of radiating sources are operating in a dense communications environment. The antenna pattern comprises the difference between two antenna receiving patterns where the beamwidth of one pattern is wider by a predetermined angular amount than the other pattern. In the preferred embodiment, a phased linear array of antenna elements is operated as two sets of elements wherein one set of elements comprising a number of elements less than the total number of elements provides a beamwidth that is broadened by a predetermined angular sector greater than the beamwidth formed by the entire array. The antenna elements are progressively phase shifted to provide overlapping beam patterns and the pattern of one set of elements is scanned so that one side of both patterns are substantially coincident.

Abstract: Compensation for the effects of environmentally caused changes and aging on piezoelectric acoustic wave devices is electrically provided by the application of a signal, such as a DC bias voltage, to the finger elements of an interdigital transducer formed on the surface of the acoustic wave device. This produces very large field concentrations at the finger edges which act to magnify the electric field and accordingly the electroacoustic effect which alters the acoustic velocity of surface acoustic waves, shallow bulk acoustic waves and reflected bulk acoustic waves propagating in a piezoelectric substrate between input and output interdigital transducers.

Abstract: A millimeter wave microstrip transmission line is coupled to a solid state echanically tunable cylindrical resonating coaxial cavity millimeter-wave oscillator by means of a probe extending linearly from the microstrip through an access slot in the cylindrical cavity wall into the zone of optimum electric field strength in the oscillator cavity to effect the translation of a TEM wave from the resonating cavity to the microstrip line at optimum power transfer and without wave mode change.

Abstract: An acoustic surface wave device is configured as a bandstop filter. The device has groups of sinusoidal corrugations cut into the top surface of a piezoelectric substrate between the input and output sets of interdigital transducers. The groups of corrugations selectively scatter certain surface acoustic wave spectral components traveling between the input and output transducers. The scattered components are converted to bulk vibration and do not impinge upon the output transducer; other components travel from input to output transducer relatively undiminished. Thus, a band of scattered surface acoustic spectral components is filtered from the input spectrum.

Abstract: A plurality of contiguous cavity pairs of multipactor input and output cavities respectively formed in two opposing ridge waveguide sections and which are mutually separated by an acceleration drift region of relatively high DC electric field strength. Both waveguide sections include means such as an RF window at one end for coupling RF power in and out of the sections while the other end is suitably terminated and additionally provides the structure which can be placed under a vacuum to properly function. The cavity pairs are arranged in a linear array subassembly within each of the waveguides and are designed to have a broadband frequency response by progressively increasing in frequency so that half power points of contiguous cavity pairs are in close proximity.

Abstract: A notch antenna for the elimination of external interference sources such jamming, self-interference, atmospheric noise and man made noise is provided by a grounded electrically conductive shield placed in the front of an omnidirectional antenna coupled to radio communications apparatus, such as a receiver, whereby the shield blocks electromagnetic waves arriving within an angular arc defined by the position and size of the shielding element.

Abstract: A method of fabricating CO.sub.2 waveguide type lasers of the type comprising a slot formed in a broad surface of a hard ceramic material, comprising grinding the slot in a conventional surface grinding machine in two steps. The first step utilizes a coarse grinding wheel and the second a finer grinding wheel. The resultant laser cavity can produce high optical power output when provided with RF excitation.

Abstract: An on-line indicator connected to each fuse of an electrical circuit includes an LED which becomes illuminated if its protected fuse blows. Groups of these on-line indicators can be connected via an OR gate to a single master fuse status indicator which also includes an LED which becomes illuminated if any of the on-line indicators connected thereto has its LED illuminated. The circuitry can accommodate power supplies of different voltages of either polarity. Opto-isolators can be used to reduce stand-by current drain and to isolate the on-line indicators from each other.