Abstract: An optical bypass switch includes a variable diffraction element responsive to acoustical signals operable to couple light signals incident to first and second input ports to first and second output ports, respectively, for a first diffraction index and from the first and second input ports to the second and first output ports, respectively, for a second diffraction index. Acoustical signals are provided by an electro-acoustic transducer coupled to the variable diffraction element which establishes acoustical signals in response to acoustical signals coupled thereto.

Abstract: An optical waveguide for transmitting light energy is defined by a glass capillary with a core of noncentrosymmetric non-linear optical polymer which has been poled to induce a stable axial alignment of molecules therein. Changes in refractive index of the polymer are induced by an applied electric field. In a preferred embodiment, the waveguide is used as an electric field sensor and may form an arm of a Mach-Zender interferometer. The device is adapted to modulate waveguided electromagnetic energy by a change in refractive index proportional to the applied electric field. In a further embodiment, the birefringent properties of the polymer are used to cause polarized light energy transmitted by the waveguide to undergo a change in polarization, which, when intercepted by a polarization sensitive analyzer, provides an amplitude modulation of the transmitted light energy.

Abstract: Interprocessor message communication synchronization apparatus and method for a plurality of processors connected to a system bus where one processor desiring to send a control signal to another processor, broadcasts an input/output write instruction on the system bus along with the address of the receiving processor and a data field representative of the control signal to be transmitted. Apparatus associated with the receiving processor includes a decoder that responds to the input/output write instruction to enable a register when the address transmitted on the bus matches its address. The enabled register receives the data signals from the bus to set therein the appropriate control signal represented by the data. The stages of the register are connected to the associated control signal inputs of the other processor. In this manner the one processor may transmit a message synchronizing interrupt to the other processor.

Abstract: A transportation container (68,44) for transporting items or enclosures (72) requiring electrostatic protection includes a box (44) lined with electrically conductive bubble layer material (58) which protrudes from open seams (66) and which is also electrically accessible through an aperture (28) in registration with an opening (42) when the box (44) is contained within the sleeve (68). The accessibility of the electrically conducting bubble sheet material (58) allows for either deliberate discharge to ground potential of the bubble material (58) via the aperture (28) or provides ample opportunity for accidental discharge to ground by virtue of protrusion of the bubble material (58) through the open seams (66). The bubbles of the material (58) distort and burst to accommodate a range of enclosures from very small to quite large by virtue of the fact that the tips of the bubbles (62) just touch without compression when the box (44) is closed.

Abstract: A digital complex correlator for correlating in-phase and quadrature components of data samples by shearing the in-phase and quadrature data pairs by a predetermined multiple of the noise in the correlation window under analysis. The sheared data is multiplied by a variable factor generated in accordance with the shearing threshold and the number of samples in the window. The variable factor is generated to maximize the precision in the data while avoiding overflows in the complex multiplication and accumulation of the correlation process.

Abstract: The character displaying capacity of a monitor is enhanced by operating the pixel clock at a frequency at which beam narrowing occurs so that adjacent pixels are substantially distinct from each other. The operating clock frequency exceeds the bandwidth of the video channel and is at a frequency higher than the clock frequency at which pixel smearing occurs.

Abstract: A digital phase-locked loop provides substantially real-time measurements of frequency differences between an applied input signal and a reference signal. The system is especially adapted for the measurement of Doppler frequency shift in a Doppler sonar detection system. A two phase clock receives a reference signal and generates complementary clock signals. A phase-frequency detector receives an applied input signal containing a frequency shift and a further reference signal derived and applied in closed loop fashion. Frequency and phase discrepancies between the applied input signal and a second reference signal are gated to a counter to increment the frequency count or blank the frequency count for a predetermined period, thereby to synchronize the second reference signal with the applied input signal in frequency and phase.

Abstract: A method and tool for use with "bed of nails" fixturized automatic test equipment for printed circuit cards for verifying the continuity of component pins with the test nails of the system where the pins of the component are not accessible from the component side of the card. A tool is affixed beneath the component to short out all of the pins thereof and a node accessible from the component side of the board that makes contact with one or more of the pins of the component (such as power or ground) is probed with the continuity probe of the system while a continuity test is performed with respect to each of the test nails associated with the pins and nodes of the component.

Abstract: A gyroscope employing a rotor in rolling contact with a ball positioned at the end of a drive shaft, the arrangement establishing a loose fitting ball and socket suspension for the rotor. Contact points of the rotor on the ball establishes the necessary pendulousities with the rotor center of gravity for damped gyrocompassing.

Abstract: A phase-locked loop compares the loop output clock with the loop input clock in a digital phase detector to provide lead/lag error signal samples. A microprocessor utilizes the lead/lag error samples to track the input clock in a wideband mode matching the bandwidth of the input and in a very narrow band mode. When the system in which the loop is utilized switches to a new input clock source, the microprocessor resets the loop divider chain so that the loop feedback signal is phase coincident with the input reference. The microprocessor tracks the new clock for a predetermined number of error samples in the wideband mode and statistically estimates, from the samples, the frequency of the input. After the frequency estimation, the microprocessor controls the loop VCO to output the computed frequency and switches to the narrow band tracking mode.

Abstract: A shock isolator apparatus of the pressurized air type having a plurality of cylinder chambers and a piston positioned for movement in the cylinder chambers. An air passage tube axially located in the piston permits air to flow between one end of the piston extending into a first end chamber in the cylinder and a chamber formed in the piston at an end opposite the one end. Air communication between the end chamber, the chamber formed in the piston, and a second end chamber in the cylinder is accomplished by air bypass ports extending between the air passage tube and the second chamber. Unidirectional pressurized valves positioned between chambers of the cylinder operate to equalize the pressure distribution throughout the cylinder.

Abstract: A synchronous counter operating from a fixed frequency time base senses the data rate of an incoming bit stream and provides a time base synchronized with the incoming data. Detection of the data rate is accomplished in real time without software or user intervention. A two-stage counter, clocked by a crystal oscillator, is triggered by transitions of bi-phase data pulses. The circuit automatically shifts the frequency of operation to conform to the incoming data rate and returns to the high speed mode upon the cessation of low speed data rates.

Abstract: The maximum and minimum depth of modulation of a carrier signal frequency modulated by a modulating sine wave is measured by a frequency counter responsive to an external gate. The external gate is generated by detecting the positive-going and negative-going zero crossings of the modulating signal and providing a gate generating trigger delayed by 90.degree. of the modulating signal less a predetermined number of cycles of the carrier. The parameters are selected such that the gate is centered around the positive and negative peak amplitudes of the modulating signal.

Abstract: A mounting method for printed circuit boards provides improved electromagnetic interference reduction while minimizing the required number of mounting screws. A conductive base plate formed with supporting members is configured to mate with a grounding circuit on the board. A central mounting screw places the board in compression to provide electrical continuity between the grounding circuit and the supporting members of the conductive plate.

Abstract: A source of light modulated by input data provides the modulated light to a phototransistor. A capacitor couples the emitter of the phototransistor to ground. A discharging transistor switch is coupled across the capacitor and a voltage comparator is coupled to the phototransistor emitter for providing a signal when the voltage across the capacitor exceeds a predetermined threshold. A microprocessor coupled to the comparator actuates the discharging switch in accordance with the comparator output.

Abstract: A remote indicator for displaying the position of a power control switch whether or not power is applied to the switch. An auxiliary DC power supply provides a reference potential to a plurality of voltage dividers. One voltage divider provides a first reference potential to a comparator. A second voltage divider and the reference power supply are connected through the power control switch so that a second reference potential is applied to the comparator when the power switch is closed. Differences of the two reference potentials corresponding to the open and closed switch positions are sensed by the comparator and used to activate an indicator accordingly.

Abstract: The automatic vacuum gripper comprises a gripper member with a resilient seal coupled to a hollow piston and shaft. The piston is spring loaded downward in a cylinder coupled to a vacuum source. With vacuum applied, the piston does not move until the gripped part is completely sealed to the gripper member.

Abstract: Apparatus for locking together modules of a computer system includes first and second members that are secured, by screws, proximate adjacent edges of adjacent modules. Tabs on the members and holes through the tabs align so that a padlock may be utilized to lock the modules together. A slotted plate is positioned on the tabs and secured in place by the padlock to cover the securing screws so that they cannot be removed.

Abstract: A synchronous decoder for recovering a train of binary data encoded in a biphase format and decoding into NRZ format. Encoded data is sampled during the first half of a bit period and the second half of a bit period and stored respectively into two storage elements. The stored data is combined and applied to a third storage element at the beginning of the next bit period. The state of the third storage element is responsive to the sequentially applied combined signals in the train of data and thereby produces a pulsed output encoded in NRZ format.

Abstract: The locking apparatus is used to secure one or more memory cartridges in a housing in a computer system module. An L-shaped member is fastened to the module by a screw in an existing threaded screw hole in the module. A second member is inserted into the module and locked to the L-shaped member by a padlock. The second member includes a first plate that fits into a clearance space between the cartridges and the housing to prevent the cartridges from being unplugged from connectors mounted in the housing. The second member includes a second plate that prevents the end of the outermost cartridge from being pulled out of the housing to clear the first plate and includes a third plate which in use covers the mounting screw of the L-shaped member so that the screw cannot be removed.