Abstract: An apparatus for decoding a Manchester encoded waveform is described in wh a gating circuit responds to the mid-cell transitions in the encoded waveform to produce an enabling signal which causes a clock circuit to generate high frequency clock pulses. A programmable counter accumulates the generated clock pulses. If the counter exceeds a clock count threshold set by a multiposition switch before the beginning of the following enabling signal, it causes a storage element to sample the encoded waveform and store the sample to provide an output signal representing decoded data. A second, substantially equivalent circuit decodes timing from the encoded waveform. The multiposition switch provides the apparatus with the capability to decode encoded waveforms of varying frequency.

Abstract: A torque balanced cable for towing or suspending oceanographic instrumenton includes a data transmission core about which is wound a helically laid inner layer of load bearing strands formed of high tensile strength, low stretch aramid fiber and having a selected pitch angle, pitch diameter and strand thickness. An outer composite layer is contrahelically wound about the inner layer and an interposed, abrasion resisting barrier film layer, and includes alternating load bearing strands and non-load bearing filler strands, the other load bearing strands having the same degree of pitch angle and thickness as the inner strands and of a number that bears substantially the same ratio to the number of inner strands as the pitch diameter of the inner layer bears to the pitch diameter of the outer layer.

Abstract: A coupling which is readily attachable to a plate, panel or like structure ncludes a rotatable shaft for thrusting a bearing element through a circular hole in the structure when the bearing element and the hole are in concentric relationship. Thereafter, the shaft is rotated by less than a complete revolution to bring the bearing element and the hole into a selected eccentric relationship, and also to activate a locking mechanism to maintain the eccentric relationship. When the bearing element and hole are in the eccentric relationship, a bearing surface of the bearing element abutts the structure to impose substantial force thereupon.

Abstract: An optical gain control device limits the light intensity incident on a podetector or photomultiplier. A fluorescent medium is interposed between a monitored source of electromagnetic energy and the detector and is irradiated by a local oscillator. The irradiation is absorbed by the fluorescent material which undergoes an electronic transition from the ground state to a first excited state. Photons impinging on the fluorescent material from the monitored electromagnetic source cause another transition to a second, more excited state. When the relaxation occurs from the higher state back to the ground, the material fluoresces. Because the magnitude of the local oscillator irradiation is kept within prescribed limits, the number of ions in the fluorescing material which are brought to the first excited state stay within certain limits. Consequently, the impinging monitored electromagnetic energy cannot excite more ions to the second higher state than were irradiated to the first excited state.

Abstract: A visual display has an increased readout capability due to its operation the transflective mode. A source of ambient light and light for radiation through the display from the backside together assure the increased readout capability. Heretofore, ambient light would degrade or washout a display making it nearly impossible for monitoring personnel to decipher alphanumeric or pictoral displays due to the decreased contrast. A pair of linear polarizers sandwich a twisted nematic liquid crystal and have their polarization axes either parallel or mutually orthogonally disposed so that the crystal will present bright or dark areas in response to applied potentials. Because a partially transmitting mirror is interposed between the sandwiched liquid crystal and the radiating light source, the ambient light augments the radiated light to enhance the visual display.

Abstract: An analog-to-digital converter using superconducting interferometers connected in parallel, each interferometer being identical. The coupling of the analog signal to each successive interferometer is increased in the ratio of 1:2:4:8:16:32:, etc. The application of a pulsed power supply to the parallel connected interferometer generates output voltages on the interferometers. The output voltages are a Gray Code representation of the analog signal.

Abstract: A fastener assembly for securing structures to the seafloor including a st of circular cross-section having a frusto-conically shaped head on a leading end for insertion into a prepared borehole and a mandril section at the other end having annular grooves around its perimeter. An expansible sleeve is disposed around the shaft in interference fit with the borehole so that when the shaft is pulled upward, the head will force the expansible member to expand against the sides of the borehole. The shaft is disposed with the grooved section extending through an aperture in a workpiece and a malleable collar is positioned around the shaft resting on the workpiece. A conventional blind riveting installation tool may be used to pull the shaft upward to engage the expansible sleeve in the borehole and to swage the malleable collar to the grooved shaft against the workpiece.

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: Optical performance characteristics of fiber optical cable components and assemblies are tested for quality in an accurate, consistent, and stable manner by the method and apparatus of this invention. The novel apparatus enables acceptability testing of a supplier's fiber optic component/assembly by comparing its optical transmission level with the level of a similar known acceptance cable or a calibration cable, the latter two cables being incorporated in the invention apparatus. Other optical parameters can be tested by this invention to determine additional line losses, such as insertion losses, optical continuity, signal modulation, etc. Stability in the test method is assured by utilizing a variable, calibrated power source.

Abstract: A system for minimizing the power requirement of a flowmeter intended for long-term unattended deployment in a current flowing through a body of conductive fluid. The system includes a pair of electrodes in contact with the fluid, and a permanent magnet which generates a magnetic field which is orthogonal to a line passing between the electrodes. An electromagnetic coil is also provided, and is selectively activated and deactivated to establish the orthogonal magnetic field at a first level during first time periods in a series of first time periods, and at a second level during second time periods in a series of second time periods. The ratio of the time duration of a first time period to a second time period is substantially less than one.

Abstract: A free spinning gyroscope is provided which has a spin axis, together with precession means for precessing the gyroscope. In addition, means are provided for detecting an electromagnetic field of energy and adapted to generate signals indicative of misalignment of the gyroscope spin axis with the energy field. Means are provided for utilizing the generated signals to directly control the precessing means to align the gyroscope spin axis with the electromagnetic field of energy.

Abstract: A precessionally aligned automatic scanning system is provided. It consists of a free spinning means which scans an electromagnetic field of radiation having lines of force whose angle of incidence is to be determined with respect to the axis of rotation of the free spinning means by detecting the angle of incidence between the axis of rotation of the free spinning means and the direction of the lines of force from the electromagnetic field of radiation. This provides an unresolved error signal representative thereof. In addition, means are provided for receiving the unresolved error signal and utilizing the unresolved error to precess the free spinning means through gyroscopic forces to cause the axis of rotation of the free spinning means to align itself with the lines of force of the electromagnetic field of radiation.

Abstract: A free spinning gyroscope is provided which has a spin axis, together with precession means for precessing the gyroscope. In addition, means are provided for detecting an electromagnetic field of energy and adapted to generate signals indicative of misalignment of the gyroscope spin axis with the energy field. Means are provided for utilizing the generated signals to directly control the precessing means to align the gyroscope spin axis with the electromagnetic field of energy.

Abstract: A free spinning gyroscope is provided which has a spin axis, together with precession means for precessing the gyroscope. In addition, means are provided for detecting an electromagnetic field of energy and adapted to generate signals indicative of misalignment of the gyroscope spin axis with the energy field. Means are provided for utilizing the generated signals to directly control the precessing means to align the gyroscope spin axis with the electromagnetic field of energy.

Abstract: An apparatus for providing increased homing capabilities in a guided miss seeker against a continuous wave radar signal by compressing the received signal which effectively increases the received signal level by more than twenty decibels.

Abstract: A method and apparatus for "masking" an aircraft or other vehicle so as to revent it from being located by an enemy radar. The vehicle is provided with means for generating and radiating a CW signal which is gated off during the reception of a radar pulse, such that a narrow gap or slot is produced in the CW signal. The reflected radar pulse in effect "falls into" this slot and hence is indistinguishable from the remainder of the CW signal as seen by the operator of the enemy radar.

Abstract: A sawtooth waveform circuit for a cathode ray tube display apparatus or the ike is disclosed for providing a sawtooth waveform signal in synchronization with the uniformly spaced pulses of a sync signal. A direct current voltage is supplied to an integrator which produces a ramp voltage. Switching means responsive to each pulse of the sync signal shorts the integrator so as to cause the ramp voltage to appear at the output of the integrator as a sawtooth waveform signal. A summing amplifier amplifies the sawtooth waveform signal, and then combines the amplified sawtooth waveform signal with a variable direct current voltage generated by a head tracker so as to provide at the output of the summing amplifier a raster drive signal.

Abstract: A training device that is a simulator of oil bilge, oil spray, and Class A fires. The device is fully controllable and imitates the appearance of a machine or engine room. Propane burners are used to provide flames, and flame and water sensors are used to monitor trainee performance. A switch controlled by a dummy valve is also included to be operated by the trainee in its proper sequence of applied procedures.

Abstract: A smoke generating apparatus is disclosed for providing a nontoxic smoke so s to simulate the smoke of a fire. The smoke generating apparatus comprises a storage tank, a smoke producing agent stored in the storage tank, and a housing affixed to the top of the storage tank. A centrifugal pump supplies the smoke producing agent to a tubular coil which superheats the smoke producing agent. The superheated smoke producing agent is then released through a solenoid valve into the atmosphere so as to form a vapor.

Abstract: A pattern generator for simulating image generation is disclosed which pets the testing of wide angle, non-programmed visual display systems including, for example, a 360.degree. non-programmed visual display system. The program generator produces a pair of composite signals, the first of which may be utilized by an annular projector to project upon a screen a sawtooth waveform pattern, and the second of which may be utilized by the annular projector to project upon the screen a checkerboard pattern so as to facilitate the testing of wide angle visual display systems.