Abstract: Expanded multilevel noise codes are generated of a type termed "code mates" aving autocorrelation functions which, upon detection in a matched filter, provide an impulse autocorrelation function. More particularly, expanded multilevel code mate pairs are generated by interleaving two multi-bit codes comprising a mate pair wherein one of the codes in each expanded mate pair comprises a code having a larger amplitude than the other code and whose position is mutually transposed in the expanded mate pairs and further wherein one of the interleaved codes is the complement or negative of one of the original or basic code mates.

Abstract: A millimeter-wave electronic phase shifter in a dielectric waveguide having a semi-insulating dielectric core and at least one semi-conducting epitaxial layer. A controller affixed to the epitaxial layer is used to apply a bias voltage thereby varying the conductivity of the epitaxial layer and influencing wave propagation in the waveguide.

Abstract: A system for monitoring the integrity of a cable, for example a cable for towing a variable depth sonar body through the ocean, is described. Such a cable comprises a core of electrical wires surrounded by load bearing wires which are secured to the sonar body through a terminator. For various reasons cracks can appear in the load bearing wires and in extreme cases one or more of the wires may break. The monitoring system includes a transducer located near the terminator where the wires are most likely to crack or break and acoustic emissions caused by the incidence of cracks or breaks are picked up by the transducer. The resulting electrical signals are amplified and passed up the electrical core of the cable to the towing vessel where they are processed. Novel aspects of the system are the water coupling between the location of the cracks or breaks and the transducer and special processing circuitry which enables breaks, cracks and electrical noise to be distinguished from each other.

Abstract: An integrated amplifier circuit for monolithic fabrication is disclosed. circuit includes a plurality of amplifier stages between an input transmission line and an output transmission line. Each stage includes a FET formed on the surface of a semi-insulating substrate such as gallium arsenide (GaAs). The gate of each FET is connected to the input transmission line, while the drain is connected to the output transmission line. The source is connected through the semi-insulating substrate to a conductive layer. A received signal propagates as a traveling wave along the input transmission line, and is amplified by each of the FETs. The phase delay between the gates is the same as that between the drains, so that the amplified signal adds constructively on the output transmission line. Each of the transmission lines is terminated in its own characteristic impedance, which may be equal to the load.

Abstract: Ferrite material to be used in millimeter wavelength apparatus is sawed ug a resin bonded diamond sawblade. A cutting speed of 5400 cm/sec is achieved by appropriate selection of sawblade diameter and spindle speed, such as 5.71 cm and 18,000 RPM. With this cutting speed and sawblade material a cut up to a maximum of 0.356 cm is possible while the ferrite is fed at from 0.0254 to 0.127 cm/sec.

Abstract: A single planar doped barrier diode is grown by the selective deposition of gallium arsenide using molecular beam epitaxy (MBE) in the center of a gallium arsenide dielectric waveguide member mounted on a ground plane. The waveguide member includes two portions which extend in opposite directions and terminating in respective metal to dielectric waveguide transition sections which are coupled to an RF input signal and local oscillator signal, respectively. The planar doped barrier diode operates as an intrinsic subharmonic mixer and accordingly the local oscillator signal has frequency of one half the input signal frequency. An IF output signal is coupled from the mixer diode to a microstrip transmission line formed on an insulating layer fabricated on the ground plane. Dielectric waveguide isolators are additionally included on the dielectric waveguide segments to mutually isolate the input signal and local oscillator signal.

Abstract: A rechargeable lithium cell is provided comprising a lithium anode, a litm intercalating cathode, and an electrolyte comprising a solution of a lithium salt such as LiAsF.sub.6 or LiAlCl.sub.4 in 24.4 mass percent 4-butyrolactone (4-BL) in dimethoxyethane (DME). The cell exhibits improved low temperature (-40.degree. C..ltoreq.t.ltoreq.0.degree. C.) performance and rate capability.

Abstract: A high capacity lithium inorganic oxyhalide electrochemical cell is provi including lithium as the anode, carbon as the cathode, and a solution of a quaternary ammonium salt in an inorganic oxyhalide solvent as the electrolyte.

Abstract: Misfit dislocation density at an InAs-GaAs interface is reduced in both InAs-GaSb and In.sub.1-x Ga.sub.x As-GaSb.sub.1-y As.sub.y superlattices grown on GaAs substrates by means of an MBE (molecular beam epitaxy) growth technique consisting of a step graded sequence of composition layers between substrate and superlattice whose composition changes in discrete concentration steps from the composition of the substrate to the composition of the superlattice.

Abstract: Miniature high frequency SC-cut quartz crystal resonators are made from a plano-plano SC-cut quartz crystal wafer by chemically polishing the wafer; then chemomechanically polishing the chemically polished wafer; then chemically polishing the chemomechanically polished wafer; depositing a suitable pattern of etch resist on the wafer using standard photolithographic techniques; chemically polishing the wafer; stripping the photoresist from the wafer; placing a suitable evaporative mask pattern into intimate contact with the wafer; depositing a suitable pattern of electrodes on the wafer; testing the resonators so formed on the wafer; selectively separating those resonators having the desired properties; mounting the selected resonators into an enclosure; adjusting the frequency of the selected resonators to the exact frequency desired; and hermetically sealing the enclosure.

Abstract: A multichannel time division multiplexed (TDM) bit stream has specific channels selected by gating selected channel bits out of a composite group of channels. The selected channel bits are spread spectrum coded as multiplexed noise codes which are then used to modulate a transmitter for communicating the codes over a transmission link. The noise codes are then automatically compressed back to original channel bits at a receiver to provide output signals which are totally non-interfering with each other.

Abstract: A covert line of sight time division multiple access communications system omprised of a plurality of geographically separated transceivers consisting of identical hardware and capable of operating either as a master station or a slave station, and when desirable as a repeater station. The system operates with a non-committed master station operating within a predetermined power circle of operation whereby multiple slave stations and/or repeaters communicate with each other by way of the master station in a one half duplex mode at a single frequency in the millimeter wave frequency range between 54 and 58 GHz.

Abstract: A method and apparatus for interleaving and deinterleaving psuedo-randomly a digital signal which is transmitted over a transmission channel is disclosed. A received bit stream is interleaved such that the order of the bits is varied in a non-random manner. The order of the interleaved bits is permutated in a pseudo-random manner and the bits are then transmitted over a transmission channel. The received bits are inverse permuted so as to return the order of the received bits to the order of the bits after the non-random interleaving step. The inverse permuted bits are then deinterleaved in the reverse order in which they were interleaved so as to reconstitute the original bit stream.

Abstract: Samples of the Sm-Fe system are directly crystallized onto heated substra by selectively thermalized sputtering with the addition of titanium as a stabilizing agent.

Abstract: A frequency synthesizer is provided that is capable of supplying a plurality of accurate frequencies. The frequency synthesizer comprises a resonator matrix including a plurality of resonators embedded in a single monolithic piece of piezoelectric crystal. The resonators are arranged in rectangular row and column configuration including m rows and n columns. Each of the resonators is separated from its neighboring resonators by distances such that the resonant energies do not overlap. Each of the rows of resonators bears a metallic electrode stripe for that row and each of the columns of resonators bears a metallic electrode stripe for that column, the electrodes row stripes being positioned on the top surface of the crystal and the electrode column stripes being positioned on the bottom surface of the crystal. The areas of overlap of the row and column stripes are registered with the central portions of the embedded resonators.

Abstract: Non laminating anisotropic boron nitride is prepared by reacting a boron halide with ammonia at a temperature of from 1100.degree. C. to 1600.degree. C. in the presence of a small amount of a volatile oxygen containing compound. The small amount of volatile oxygen containing compound is sufficient to prevent lamination yet small enough to prevent the finalized product from losing its anisotropy.

Abstract: A magnetically tuned band reject filter for millimeter wave frequencies crising a barium ferrite sphere embedded in the upper surface of a semi-insulating gallium arsenide waveguide transmission line element located on a conductive ground plane and forming thereby an image guide. A pair of high energy rare earth permanent magnets are located on the upper and lower surfaces of the waveguide element at the location of the ferrite sphere with a single tuning coil surrounding both the magnets and the waveguide and operates to bias the ferrite sphere for selective absorption of signals propagating along the transmission line. With the magnetically tuned ferrite sphere located therebetween, both an input signal and a local oscillator signal, for example, are coupled to one end of the waveguide element while receiving electronics apparatus, such as a Schottky barrier diode mixer, is located at the other end of the waveguide element.

Abstract: Carbon black powder is pretreated with acetone or methanol prior to cathode abrication to improve the cathode operating voltage and increase the cathode life of lithium sulfuryl chloride electrochemical cells.

Abstract: Enhancement of proper phase and insertion loss response, reduction of undesired mode couplings, and greater latitude in the design with respect to energy trapping in filters, in addition to enhancement of the dynamic frequency-temperature compensation, as well as stress-frequency compensation is provided by arranging the electrode gap of a monolithic crystal filter so that it is perpendicular to the projection of the normal coordinate or eigenvector of the mode utilized along with making the side edges of the electrodes parallel to the direction of the normal coordinate projection. For the doubly rotated SC cut of quartz, using the c-mode, the normal coordinate projection angle, i.e. the axis along which the electrodes are aligned, is substantially 8.2.degree. from the rotated plate (X') axis.

Abstract: Multilevel code mates A and B expanded in accordance with the expression , b.sup.K and B=a.sup.K, b are compressed to a lobeless basic mate pair by repeatedly compressing corresponding code mate pairs in successive stages to provide diminishing codes of half the code length by amplifying the code mates by a predetermined amplification factor and then adding and subtracting the code mates in accordance with the expressions A.sub.i-1 =A.sub.i +B.sub.i.sup.K.sbsp.i and B.sub.i-1 =A.sub.i.sup.K.sbsp.i -B.sub.i where i is the i.sub.th compression stage and K.sub.i is the amplification factor applied to the codes A.sub.i and B.sub.i.