Abstract: Tributenyltin compounds containing double bonds at C-1 or C-3 or combinats thereof are synthesized from symmetrical tetrabutenyltins to offer a sufficient toxicity to function as a biocide or an antifoulant compound for ships' hulls and have an increased rate of degradation to be compatable with the environment.

Abstract: The invention converts the voltage output of a DC source to a higher voltage. A germanium transistor start-up circuit receives a DC supply voltage input and includes an astable multivibrator which produces a square wave voltage output that is transformed to a substantially DC steady-state voltage output by a transformer and a capacitor. This elevated voltage is provided to an oscillator circuit which provides two square wave outputs. Each output is provided to an array of invertors operably coupled to an array of field effect transistors. The transistors are operably coupled to a power transformer. The square wave outputs of the power transformer are full wave rectified to provide a DC output having a higher voltage than the system input voltage. The power transformer also provides another full wave rectified voltage which disables the start-up circuit to eliminate parasitic energy losses attributable to its continued oscillation.

Abstract: A transducer array designed for towing at an extended distance behind a sace vessel includes electroacoustical transducer elements connected in opposition to the active elements of the array. A surrounding acoustic isolation structure effectively isolates the dummy transducer elements from the ambient noise field while permitting cancellations of self-induced noise.

Abstract: A clamping method and apparatus for applying the necessary pressure to an sembly of metal parts during diffusion bonding and/or superplastic forming of the parts. Basically, the apparatus comprises a pair of opposed generally L-shaped frames having a cavity therebetween for holding the assembly of parts and associated shaping tooling. The frames are pivotable about a hinge connecting first ends, with a mechanism at the opposite ends for moving the frames together in a clamping manner or apart to allow access to the cavity. The tooling within the cavity typically includes a pressure vessel having a housing containing ceramic forming members having an internal volume within which metal parts to be shaped and/or bonded are placed. The parts are subjected to heat and pressure during processing. This apparatus and method are particularly suitable for manufacturing elongated metal products having a generally box-like cross section.

Abstract: A transversal filter uses optical components to provide for a wide bandwi, greater than 10 GHz signal processing capability. rf modulated optical signals are fed over different lengths of optical fibers to impart appropriate tap delays and each is coupled to an integrated optical coupler. Each of the integrated optical couplers have the capability to introduce variable positive and negative weights. Incoherent summing means receive the modulated signals and feed them to an interconnected detector to thereby provide appropriate positive and negative variable weighted signals.

Abstract: An interference canceller for cancelling an interfering signal generated by n interfering source from a transmission link between an antenna and a receiver. The interference canceller derives a sample of the interfering signal from the interfering source and down converts the sample to an intermediate frequency. A computer controlled delay path and computer controlled amplitude and phase modulator interatively adjusts a cancellation signal that is injected into the transmission link between the antenna and receiver to maximize the amplitude match between the cancellation signal and the interfering signal, and anti-phase the cancellation signal with respect to the interfering signal.

Abstract: A receiver test apparatus that injects a plurality of attenuated test sigs into a receiver under test is improved by contemporaneously injecting a test message to identify the level of the attenuation test signals so that an operator may easily identify the level at which receiver anomalies occur. The test signals and messages are programmed so that testing may be easily reproduced.

Abstract: A method detects incomplete coverage of hermetic coatings applied to opti fibers during in-line optical fiber fabrication procedures as well as off-line applications. A fluorescent material surrounds the core region of the optical fiber prior to the formation of the hermetic coating on the optical fiber and energy is radiated in the optical fiber to propagate in the cladding mode. This causes an excitation of the fluorescent material to fluoresce in response to the propagated energy. An appropriately disposed detector detects levels of emitted fluorescence along the length of the optical fiber to indicate where the hermetic coating is incomplete or where pinholes in the hermetic coating are located. Optionally, the fluorescent material is located outside of the cladding layer, inside of the cladding layer near its outer surface or throughout the cladding region to fluoresce when excited by the propagated energy.

Abstract: A multi-post gimbal mechanism for imparting motion to an object about a cer of rotation including a frame for supporting the object and a plurality of elongated posts coupled to the frame so as to permit orbital rotation of the frame about each of the coupling points. Each of the elongated posts is selectively adjustable in position and drive means are coupled to the elongated posts to selectively adjust the position. The drive means are supported on a mounting base and are pivotally attached to the mounting base such that each drive mechanism can rotate about an axis that is orthogonal to the longitudinal axis of its corresponding elongated support post.

Abstract: A precision Doppler effect compensator provides Doppler compensation in astic transmission by simultaneously sending a known reference signal with an information signal. The information signal and reference signal undergo identical Doppler effects. The compensator uses the Doppler shifted reference signal to sample the analog Doppler affected information signal. The analog information signals are digitally converted and stored in a first in first out shift register. The samples are read out of the FIFO at a rate corresponding to the frequency of a non-Doppler shifted reference signal so as to precisely reconstruct the information signal as transmitted. The samples read from the FIFO are reconverted from digital to analog form to be presented to a receiving modem for further information processing.

Abstract: A suspended substrate rat-race coupler utilizes an elliptic configuration of the usual circular rat-race coupler on a circuit card positioned within below cut-off suspended substrate housing channels. The channels within the suspended substrate housing are positioned to receive the arms of the elliptical rat-race coupler. The longitudinal axis of two of the suspended substrate channels are offset with respect to each other to accommodate the rat-race arms and are positioned either on the same side of a primary suspended substrate channel or on opposite sides of the primary suspended substrate channel. Connections to the four ports of the rat-race can thus be made without disrupting the TEM propagation mode within the suspended substrate device.

Abstract: An apparatus and method of improving the resolution of a linear FM signal s(t)=a(t)cos .phi.(t) where .phi.(t)=2.pi.(s.sub.o t+.alpha.t.sup.2) is provided by a modified computation of the Wigner-Ville Distribution. An analytical signal ##EQU1## is translated or calculated from the received linear FM signal r(t) so that a Wigner-Ville Kernel sequence ##EQU2## is formulated. An analysis of the frequency of the kernel sequence follows in accordance with a high resolution estimation technique that may include a kind of a least squares approximation fit or an eigenvector spectral estimator such as MUSIC OR ESPRIT to provide an improved time/frequency representation having a resolution of about an order of magnitude better as compared to a conventional discrete Fourier transform frequency analyze of the kernel sequence.

Abstract: A torpedo ejects lead weight at the conclusion of a practice run and is bed to the surface for recovery and reuse. A squib is initiated to release the weight by a control circuit which is actuated when the torpedo engine stops. An appropriately interconnected transistor and field effect transistor respond to built-up charges on three charge storage circuits to assure the proper initiation of the squib when the torpedo stops running. The stored energy thus is brought into effect to assure reliable separation and avoids the problems otherwise associated with conventional electromechanical relays.

Abstract: An intelligent security assessment system includes a multiplicity of sens for detecting intrusion into an area. Each of the sensors operates on a different principle to detect intrusion. For example, sound, vibration, infrared, microwave and light level sensors are used. A computing system receives the outputs of each of the sensors and is programmed to provide an output based upon an algorithm that minimizes the likelihood of a false indication of intrusion by the intrusion sensors. Each sensor has an on and an off state and the computing system assigns a weighting factor for each sensor that is in the on state. The computing system sums the weighting factors and compares this sum to a reference and then provides a further output when the sum exceeds the reference. This computing system output is utilized to activate an additional intrusion detector such as an ultrasonic detection system and also to activate a video surveillance camera for observance of the area where the intrusion is indicated.

Abstract: A radar transmission, reception and signal processing system generates high esolution synthetic aperture radar ground maps from air or space platforms using waveforms in which frequency is changed pulse-to-pulse. The transmitted radar signal is comprised of a series N bursts with n pulses per burst wherein each of the pulses is a fixed frequency step, .DELTA.f, either above or below one or the other of the n pulses, i.e. the n pulses comprises an ordered set and further, preferably, wherein the set of n pulses is arranged in time as a random permutation of the ordered set. In each of the k sample gates for each burst the n complex samples of reflectivity are inverse Fourier transformed from frequency domain samples of reflectivity to synthetic range domain profiles to result in an array of aligned range profiles in each of k coarse range delay positions.

Abstract: An optical interference filter has narrow linewidth and wide acceptance ae and includes a hemisphere coated to provide a narrow bandpass filter at a desired wavelength at normal incidence while other wavelengths at normal incidence are absorbed or reflected. A photodetector placed at the center of the hemisphere detects the desired wavelength only. Other wavelengths that are shorter than the wavelength of the filter are transmitted through the filter to be absorbed by a black absorbing surface around the photodetector. Thus, only the frequency of interest at normal incidence provides a representative signal at the detector.

Abstract: Target discrimination involves processing of sonar echoes in the time-dom and using features of the targets that the human auditory system uses (time separation and amplitude of echo highlights). Known targets are placed in the water and ensonified by multiple broadband transient signals. Echoes from each of the known targets have time-domain feature data extracted and stored to construct a library of known target features. Unknown targets echoes of transmitted multiple broadband transient signals are received and time-domain feature data is extracted from these. A comparison of the unknown target echo features with the known target echo features provides a discrimination of the unknown target echoes.

Abstract: Tracking and location of a high speed water rentry vehicle is assured by the inclusion of an acoustic source. An acoustic generator in the form of a piezoelectric transducer is potted in polyurethane and fills a volume aft of a disc-shaped wall in the re-entry vehicle. The potting compound couples the acoustic generator to the metal skin to enable acoustic transmission from the vehicle to the tracking range. Optionally, a layer of material is interposed between the potting compound and the vehicle's metal skin to aid in acoustically coupling the generator's output to the metal skin. No structural modifications of the entry vehicle are required yet the pinger is capable of sustaining re-entry shock.

Abstract: Improved dynamic range resolution or accuracy analog to digital conversion ses linear prediction. An open loop or feed-forward architecture passes an analog signal to a coarse or orthodox analog-to-digital converter that provides digital signals representing a most significant part of the output signal and offers them as inputs to a digital linear predictor whose digital output signal is reconverted to analog form and fed to an analog adder. An analog delay device may be used to receive the next analog sample and, after the proper delay (if needed), feed it to the adder where the difference between the analog predicted value and the analog signal is determined and passed to a subsequent coarse or orthodox analog to digital converter. A closed loop or feedback configuration receives the analog input signal data as well as a feedback predicted value in analog form and passes the difference to a coarse or orthodox analog to digital converter.

Abstract: An infrared imaging system is presented wherein a visual image of a scene being viewed is obtained from the thermal energy radiated from said scene. The thermal energy radiated is focused onto a plurality of means for absorbing energy from the infrared radiation, specifically a two-dimensional array of gas cells with the front end being a rigid infrared transparent window, the sides being rigid, and the rear ends being flexible membranes. Infrared radiation absorbed by the cells causes changes in the thermodynamic pressure within each cell and consequent expansion of the flexible membrane on the rear end of each cylindrical cell. The deflection of these flexible membranes is monitored and measured by either a laser interferometer system or a solid state pressure sensing system. Measurement of this deflection represents the amount of infrared radiation received at each of the plurality of gas cells.