Abstract: An apparatus for extracting, storing and repetitively replaying a broadband atasample is fabricated from proven electronic components to assure long term reliability and reproducibility. A broadband acoustic signal is digitized and stored in a RAM until it is loaded with the desired signal. An adjustable clock controls the rate at which the stored signal is loaded and repetitively displayed so that its spectrum and characteristics can be fully analyzed. Appropriate filters are provided on the input and output sides to block incoming signals outside of the range of interest and those signal components attributed to the variable clock. Selection of particular portions of the stored desired signal may be addressed for detailed analysis on a repetitive basis if needed.

Abstract: Longitudinal tensile and/or compressive strain in optical fibers is detered by an entirely optical technique. A test optical fiber optically coupled to optical injection and extraction couplers form an optically recirculating loop. A semiconductor laser diode feeds a series of narrow light pulses into the loop via the injection coupler and an oscilloscope or signal peak detector give visual indications of optical correlation when an avalanche photodiode provides responsive signals coming from the extraction coupler. Straining the optical test fiber will change the loop's length and, hence, the time delay between reoccurring pulses so that the loop frequency of the narrow optical pulses must be correspondingly changed to provide maximum signal correlation. Changing the pulse repetition rate of the laser diode until a maximum correlated signal is observed at the scope or detector provides a new resonant loop frequency that is proportional to strain.

Abstract: A missile having a payload mounted on an airframe includes a pair of wave aped springs for separating the payload from the airframe at a predetermined time in the flight envelope. Hinged clamshell-half fairing members in the airframe support the payload during the initial stages of deployment by a rocket motor. At the predetermined time an explosive band separation device is actuated so that the pair of diametrically disposed wave-shaped springs can force the clamshell-half fairing members apart and into the slipstream to disengage the airframe from the payload to assure its intended deployment.

Abstract: A method and apparatus of transmitting optical data through a wall separag a first fiber in a first medium from a second fiber in a higher pressure medium assures optical information transfer. A bore is provided in the wall having an inwardly extending annularly rim. A cylindrically-shaped optical glass plug is sized to fit within the bore and configured to abut the annular rim and a hard solder seal, a ceramic seal or a fused frit is disposed between the bore and the glass plug to hermetically seal one side of the wall from the other. A quarter-pitch graded-index of refraction rod lens contacts opposite sides of the optical glass plug and the first and second optical fiber are held in an aligned relationship with the rod lenses and glass plug to assure bidirectional transmission of optical data. The apparatus and method assure reliable optical transmission with long term stabilities in high pressure differentials.

Abstract: A programmable time varying attenuator has a reprogrammable digital circuit or impressing an analog attenuation signal on a continuous wave noise signal. This signal is fed to the input of a receiver and since the digital circuitry can be reprogrammed with a known sequence to effect a desired analog attenuation, a receiver's performance can be monitored and evaluated when the attenuated signal or error signal is simultaneously received with information signals. A desired time relationship between the information signals and the time varying attenuating test signal or error signal is maintained since both are slaved to a common standard. The programmable time varying attenuator is programmable independent of the information signal source and, therefore, is adaptable with different sources while being a highly reliable and cost effect device for system testing.

Abstract: A number of viewers wearing polarized glasses are presented real-time, hiresolution, three-dimensional projected images on a distant screen at video image signal rates. Two laser raster scanners each activate a separate one of two liquid crystal light valves with information representative of left or right eye images. A high intensity light source is polarized through a prism so that one component is directed to one liquid crystal light valve and an orthogonal component reaches the other liquid crystal light valve. Both components of the high intensity light are modulated by the valves and reflected back through the prism onto the distant screen. Laser diodes and solid-state vertical and horizontal deflection components in the laser raster scanners combined with the liquid crystal light valves and a single bi-polar prism result in a reliable, compact unit capable of providing long term economical displays.

Abstract: A electrooptic systolic array architecture performs matrix-matrix multiplication using incoherent light. The incoherent light is collimated and passed through a polarizing beamsplitter and onto a pair of optically reflecting light valves. Each of the valves has a number of cells which are continuously being updated in a clocked sequence to vary their reflectivity in accSTATEMENT OF GOVERNMENT INTERESTThe invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Abstract: A machine is provided for grinding the top surface of an annular body. The achine includes a block which is receivable within the annulus of the body. The top of the block has a central hole. A plurality of rods slidably extend transversely through the block with a first end of each rod extendable into the hole and a second end of each rod extendable from a side of the block opposite the inside curved surface of the annular body. A plurality of arcuate pads are provided wherein each pad has an arc which conforms to the curve of the inside of the annular body. Each pad is connected to a respective second end of each rod. A bolt is threaded into the central hole of the block, the bolt having a bottom tapered portion for engaging the first ends of the rods so that when the bolt is threaded into the block the rods will be forced outwardly to engage the arcuate pads with the inside curved surface of the annular body. A turntable is slidably mounted on the top of the block.

Abstract: A method and apparatus is provided for detecting and rejecting spurious sals that may arise in incoming data. A remotely disposed data producing sensor for each sensor data channel and a single blind data channel extend to a receiver or a recorder. A data link is provided linking each sensor channel to the recorder and a one-shot multivibrator generates a sensor channel pulse whenever a signal having less than a predetermined rise time and exceeding a predetermined magnitude comes through the sensor data channel. Another one-shot multivibrator coupled to the blind channel generates a blind channel pulse whenever a signal satisfies the same conditions as for the sensor channel. An AND gate associated with each sensor data channel initiates an interruption of the data link for the duration of a coincident receipt of the sensor channel pulse and the blind channel pulse to connect a d.c.

Abstract: A method and apparatus deploys a hydrophone array in a predetermined patt. A master buoy includes a float and an anchor which hold a central portion at a predetermined depth in the water. A number of hydrodynamically shaped glide vehicles are disengaged from the central portion and glide radially outwardly from it. When the glide vehicles come to rest, strings of hydrophones are released and buoyed along the bottom in a preestablished pattern. Acoustic energy impinging on the hydrophones, optionally is fed to a transmitting unit on the float or to a remote installation via a cable lying on the bottom.

Abstract: An apparatus and method of transmitting and receiving information underwa assure improved performance characteristics. Modulating a carrier and appropriately filtering it allows the transmission of only single sideband signals or a carrier along with single sideband signals to increase the range at reduced power consumption levels. Demodulating incoming signals can be done synchronously (when the carrier is present) or asynchronously (only single sideband signals) to extract the information. When a number of carriers are modulated and, simultaneously, are transmitted and received, the system's reliability is enhanced.

Abstract: An apparatus and method for measuring the diffuse absorption coefficient of seawater provides reliable readings. An emitter of pulsed light is disposed below the water's surface and an irradiance receiver is located between the pulsed light emitter and the water's surface. Because the irradiance receiver is facing downward, is separated from the light emitter a given amount and may be disposed a suitable distance below the water's surface, reliable day and nighttime readings are obtained that are unaffected by atmospheric or surface conditions.

Abstract: A hydrophone deployment apparatus is provided for an underwater vehicle, rein the apparatus includes an annular drum releasably mounted about the tail portion of the vehicle. A plurality of arms are pivotally connected to the aft portion of the drum and are capable of swinging from forward positions flush with the vehicle to aft positions behind the drum. A device is provided for enabling retention and selective releasing of the arms from the forward flush positions. A hydrophone is releasably mounted on the inside of one of the arms, and a cable is connected between the hydrophone and the vehicle with an intermediate portion wound on the drum. With this arrangement a release of the arms during travel of the vehicle will cause the drum to be released and the vehicle will swim away from the drum pulling the cable until it is completely off the drum, at which time the hydrophone is pulled from its mounting in the arm. At this time the drum is jettisoned and the hydrophone becomes operational.

Abstract: The output signals of a number of variable transconductant multipliers are inerized so as to enable a triple product convolver to calculate Fourier transforms or produce beam forming of signals more accurately. Each of the multipliers includes a differential transistor pair, a current source and an emitter follower all properly interconnected together. The current source and emitter follower function as a linear voltage-to-current converter while differential transistor pair provides for linearity over a preestablished dynamic range. Such linearity is assured by a capacitor coupled between the emitter-base junction of the input transistor of the differential transistor pair. This capacitor has a magnitude equal to the sum of the stray circuit capacitance between the emitters of the differential transistor pair and ground plus the difference between the emitter-base capacitances of the differential transistor pair.

Abstract: Improved performance in a fiber interferometer gyro results from eliminat signals attributed to unwanted reflections from the fiber ends and the coupling lenses. A coiled single-mode fiber bidirectionally transmits beams radiating from a continuous wave laser to a detector. A fixed frequency oscillator amplitude modulates the laser output and provides a reference signal at the same frequency to enable synchronous detection of the detector output signals. Shifting the reference signal .pi./2 radians from the modulating signal eliminates the detector output signals which are attributed to reflections from the fiber ends and coupling lenses. By properly selecting the modulating frequency and reference phase, the information validity of beam signals passing through the coiled single-mode fiber is enhanced.

Abstract: An electro-optical modulator/antenna operates in the tunable diffraction ting mode to vary the magnitude of the zero diffraction order and consequently transmits optical information. A relatively thin slab of lithium niobate or equivalent electro-optic material has its lateral surfaces optically polished and its C-axis, or optical axis, running parallel to the polished lateral surfaces. At least one set of interdigital metallic electrodes are deposited on the face or just within the lateral surfaces to form, among other things, a diffraction grating that is orthogonally disposed with respect to the C-axis. When a potential source is coupled to the interdigital electrodes, the electric fields between adjacent electrodes change the crystal's index of refraction in accordance with the linear transverse Pockel's effect.

Abstract: A coupling ring is bonded onto the opposite ends of a ferroelectric stack ving substantially the same thermal expansion coefficient as the stack. A thin film of silicone compound is wiped onto the axially exposed surfaces of the rings and surfaces provided in a head and a tail mass are configured to mate with them. A plurality of microspheres are mixed uniformly through a liquid adhesive and this mixture is coated onto the suitably shaped surfaces on the head and tail mass. A stress rod reaching between the head and tail mass axially compresses the ferroelectric stack and excess adhesive mixture is squeezed from between the mating surfaces. The thickness of the liquid adhesive is restricted to the diameter of the microspheres to ensure a high impedance match and upon applying the proper amount of heat, rigid joints are set up between the now hardened adhesive and the head and tail mass.

Abstract: A manifold controls the venting of pressurized gas from an ordnance launc. A manifold block is provided with a number of passageways which communicate with a pair of recesses machined in the block. A high pressure gas valve is disposed in one of the recesses while a venting valve is rotatably positioned in the other recess. Ports are included in both of the valves so that when they are rotated a venting sequence of the launcher is effected. A specifically configured handle is secured to each of the valves and a spring biased pawl engages a number of teeth on the venting valve handle to allow only one direction of rotation. The configurations of the handles, the ratchet and pawl ensure a preestablished venting sequence and readying of the launcher for another shot.

Abstract: An improvement for a stereoscopic system synchronizes a video monitor and a eft-and right-eye viewer. Synchronous operation at a field-by-field rate is triggered by coincidence and noncoincidence of horizontal sync pulses with coincidence pulses derived from the horizontal sync pulses. As a result, the field carrying the left eye image is always connected to the left eye lens of the viewer and the field carrying the right eye image is always coupled to the right eye lens of the viewer.

Abstract: A single composite cable is deployed between adjacent monitoring stations r sensing an intruder. A number of piezoelectric elements disposed in the cable provide electrical intrusion signals when they are disturbed. Power and triggering pulses for the stations are fed through the cable by a pair of electrical conductors and optical signals representative of the intrusion signals are fed through at least one optical fiber. As a result, the composite cable is relatively lightweight and compact to simplify deployment and it avoids the problems normally associated with crosstalk.