Abstract: A ship-borne sonar heave compensation system measures the heave at time of transmit and at the expected time of receive of a bottom-echo which is approximated by the previous depth determination corrected for heave. Using these values of heave, the depth of the detected bottom-echo is corrected to provide the true depth corrected for heave. A chart recorder reads out from memory the sonar return signals, including the bottom-echo, corrected for these heave values to present a true picture of the bottom contour.

Abstract: A traveling wave tube made in accordance with this invention wherein the folded waveguide interaction circuit and the input/output transitions to standard waveguides are made of a single piece of metal such as oxygen-free, high conductivity copper. By manufacturing the folded waveguide circuit and the input/output circuit-to-standard waveguide transition out of one piece of material, VSWR on the order of 1.1:1 is expected for traveling wave tubes intended to operate at 94 GHz. Furthermore, this invention minimizes expensive tooling and labor while providing a higher yield of traveling wave tubes.

Abstract: The cathode and tube of this invention comprise a secondary emission semiconductor cathode in a crossed-field high power amplifier. A gallium arsenide semiconductor doped with an impurity to make it more conductive than intrinsic gallium arsenide has been found to perform better than prior art secondary emission cathodes when it is incorporated as a cathode in a high-power crossed-field amplifier tube operating at high average and peak current. With a gallium arsenide cathode, the crossed-field amplifier tube exhibits a radio frequency output pulse which has fast rise time and much reduced leading-edge jitter relative to performance of the same cross-field amplifier tube having a conventional secondary emission cathode.

Abstract: The cable of this invention comprises a pair of solid, flat, flexible electrical conductors of beryllium-copper attached to a reinforcing webbing of braided nylon. The ends of the conductors are soldered to electrical connector sockets and pins which are supported by glass reinforced resin disks. The webbing is tensioned while being molded inside a water impermeable elastomer which also encompasses the conductors, disks, and end portion of the sockets and pins. A second molding operation covers the water impermeable elastomer with a tough elastomer to form the cable including integral connector bodies incorporating the sockets and pins.

Abstract: A tuning structure for a klystron oscillator is provided by a set of holes extending part way through cavity walls of the klystron. The holes provide weakened portions in the cavity walls which permit an inward depression of the walls at the sites of the weakened portions for adjustment of the central frequency of an oscillation band. Thereby, deformable tuning diaphragms, which are employed for altering the oscillation frequency within the oscillation band, need not be deformed for an oscillation at the center of the desired band. Variations in frequency can thereby be accomplished without metal fatigue, such fatigue having occurred when the diaphragm has been utilized for setting the central frequency of the oscillation band.

Abstract: A pulse duration modulated (PDM) signal is generated from a periodic digitized signal which may be produced by sampling an analog signal of frequency F.sub.s and using a digitizing frequency F where F>>F.sub.s. Linearity of the analog signal between sampling points is assumed. A computer solution of the intercept of the assumed straight line between each pair of successive sample values of the digitized signal and a reference triangular waveform of frequency F/2 provides the time interval between intercepts from which the interpolated pulse duration modulated (IPDM) waveform is generated. A method to add low frequency signals in the IPDM domain, useful for providing Class AD amplifiers with a feedback path and for summations of input signals without converting signals back to analog form, operates on the sum of the respective intercept times of each of the signals. The summed intercept times are used to provide an IPDM signal which represents the sum of the original digitized signals.

Abstract: A pulse duration modulated (PDM) signal is generated from a periodic digitized signal which may be produced by sampling an analog signal of frequency F.sub.s and using a digitizing frequency F where F>>F.sub.s. Linearity of the analog signal between sampling points is assumed. A computer solution of the intercept of the assumed straight line between each pair of successive sample values of the digitized signal and a reference triangular waveform of frequency F/2 provides the time interval between intercepts from which the interpolated pulse duration modulated (IPDM) waveform is generated. A method to add low frequency signals in the IPDM domain, useful for providing Class AD amplifiers with a feedback path and for summations of input signals without converting signals back to analog form, operates on the sum of the respective intercept times of each of the signals. The summed intercept times are used to provide an IPDM signal which represents the sum of the original digitized signals.

Abstract: The transducer of this invention provides a one-to-one input-to-output frequency relationship by the use of different magnetostrictive materials within the same transducer, the materials each having positive and negative strain expansion coefficients. The materials are selectively driven so that the transducer motion is in one direction for one polarity of the sinusoidal drive signal and in the opposite direction for the other polarity of the drive signal. The resultant transducer is capable of greater peak-to-peak excursion of the radiating face for the same length of magnetostrictive material than in the prior art biased-material transducer.

Abstract: A composite layered assembly of piezoelectric polymer layers and printed wiring layers are configured so that plated-through holes make electrical connection from the outputs of a plurality of polymer hydrophones formed on one or more polymer layers to a plurality of output conductors on a single plane after each hydrophone output is amplified in its associated amplifier.

Abstract: A microwave circuit for combining the high output power of two phase and amplitude controllable amplifiers (e.g. magnetron amplifiers) is described. The circuit uses a "Magic T" circuit to reduce the magnitude of the amplified power which must be dissipated by a low-power ferrite circulator connected between the input signal source and the Magic T. Phase and amplitude comparators are used to control the amplifiers so that they may be combined in the Magic T.

Abstract: A digital sound synthesizer produces a variable spectral line width to synthesize tones by accumulating phase quanta sequentially for each of a set of tone samples. The rate of accumulation of phase for each tone is randomly altered with preset values of phase increment to broaden the spectral line. The broadened spectral lines provide a display with a spectral presentation of sounds more closely resembling naturally occurring sounds. The embodiment shows how one-hundred non-harmonic frequencies can be generated (using integrator 64), each of which can be independently amplitude controlled and band-width modulation controlled using random deviation of a sine wave.

Abstract: A thermal head drive circuit with the input connected to a source of printing data and the output connected to a thermal head including a linear array of heater elements improves the printing speed of a thermal head recording apparatus when printing successive lines. Improved printing speed is effected by simultaneously energizing each heater element with the time of energization for any one heater element being determined by the shade of gray to be produced by that one heater element.

Abstract: A broadband doppler simulator is described in which signals from a plurality of hydrophones are simulated by selecting storage addresses of a random access memory whose successive addresses contain samples of an input signal. The range of each hydrophone from the target whose signal it is receiving is determined by the address assigned to the hydrophone relative to the address of the input signal in the random access memory. In order to produce a doppler shift (time compression/expansion), the address of the simulated hydrophone signal is changed with respect to the signal which is being stored in the memory. The rate at which the address of the simulated hydrophone signal is being changed relative to the input signal determines the doppler shift.

Abstract: A pulse duration modulated (PDM) signal is generated from a periodic digitized signal which may be produced by sampling an analog signal of frequency F.sub.s and using a digitizing frequency F where F>>F.sub.s. Linearity of the analog signal between sampling points is assumed. A computer solution of the intercept of the assumed straight line between each pair of successive sample values of the digitized signal and a reference triangular waveform of frequency F/2 provides the time interval between intercepts from which the interpolated pulse duration modulated (IPDM) waveform is generated. A method to add low frequency signals in the IPDM domain, useful for providing Class AD amplifiers with a feedback path and for summations of input signals without converting signals back to analog form, operates on the sum of the respective intercept times of each of the signals. The summed intercept times are used to provide an IPDM signal which represents the sum of the original digitized signals.

Abstract: Phase locking of the output signal of a magnetron with a frequency source signal is obtained by a phase comparison of the output signal and source signal to obtain an error signal which energizes a winding of the magnetron magnet to thereby change the flux experienced by the magnetron tube operating in conjunction with frequency pulling of the magnetron output signal by the source signal coupled to the magnetron by a three-port circulator.

Abstract: A tilt-angle electron gun provides a conical beam of electrons for injection into an axially aligned magnetic field of a gyrotron tube. The beam is formed by an electrostatic lens system for focussing and accelerating the electrons within a magnetically shielded region. The conical beam is substantially monoenergetic and laminar so that after injection into the magnetic field the resulting hollow beam has gyrating electrons which have an axial velocity spread sufficiently low for high efficiency gyrotron amplification.

Abstract: A fairing segment for a cable is of composite construction which combines an elastomeric fairing body with a flexible spring-steel clip in the fairing nose. The elastomeric body allows the fairing nose to conform to the cable catenary in the flow stream, presents a smooth leading edge of the flow, and reduces drag. The clip is flexible in the direction of the plane of the fairing to conform to bending of the cable over sheaves or in the water. The spring steel clip allows the fairing to freely rotate about the cable and to align with the flow stream by maintaining low interfacial friction between the cable and the fairing. The clip also minimizes or prevents cold flow of the elastomeric nose portion of the fairing segment into the interstices of the cable armor. The tail portion of the elastomeric body is stiffened to prevent cupping or bending which would cause kiting of the cable.

Abstract: A pneumatically controlled electrical test connector contains spring loaded pins whose ends are brought into electrical contact with the opposing ends of corresponding connector pins of an electronic module. The pins of the pneumatically controlled connector have recesses in one of their ends to center the ends of the module connector pins. Pneumatic cylinders produce substantial force between the opposing pins of the test and module connectors to thereby cause good electrical contact at the contacting pin ends. The spring on each pin accommodates the mechanical tolerances of the pin lengths and causes the force on each pin to be substantially equal. Commercially available connectors are slipped onto the other ends of the test connector pins for wiring of the test connector to a test set.

Abstract: A bladder shaped to conform to the form of the sonar transducer housing of a torpedo in which it is located compensates for volume changes because of temperature changes of the oil which fills the transducer housing. The bladder also compensates for the change in water pressure produced by the depth at which the torpedo is operating. The bladder is sufficiently stiff so that it maintains a predetermined shape substantially midway between its fully extended and fully compressed position during the time that the housing is air evacuated and then filled with oil at near atmospheric pressure. The bladder is thus capable of expanding or contracting to accommodate changes in the volume of the contained oil as the temperature of the oil changes. The bladder is preferably made of a material without substantial spring force or stretch.

Abstract: Apparatus is provided for the automated handling and testing of semiconductor electronic modules which are stored in successive slots along the length of a magazine or container. The magazine is moved lengthwise in step-wise fashion and indexed to cause each module to assume in succession a position over an electrical connector. The connector is mechanically moved to make electrical contact with the electrical connector of the module. The module is thereby connected to an electrical test set which tests the module and provides a signal indicating whether the module has passed or failed and the module is so marked. The modules sequence through the test procedure until all have been tested, at which time the magazine is returned to its initial position.