Abstract: A transducer for transmitting and/or receiving acoustic energy under water includes a head mass, a tail mass, and an active motor/generator section which includes piezoelectric elements active in the shear mode of operation. Another embodiment illustrates a transducer of a bender configuration.

Abstract: The position of a carrier from a navigational reference generates X,Y coordinate navigation signals which are scaled as distance along a TV line of a TV display and a line number in the frame of the TV picture. A continual updated track of a moving vehicle is therefore displayed on a TV monitor, and if a video disc is used, can be recalled from the non-volatile memory for later replay.

Abstract: An energy imaging system providing high resolution at the center of the field of view and reduced resolution as a function of the distance away from the center.

Abstract: A standard television picture is transmitted over conventional phone lines by sampling and storing one picture element per TV line, and transmitting the information of the stored samples over the phone line as a reduced bandwidth television signal. At the receiver end the transmitted signal is placed into storage and extracted at standard TV rates and written as a TV line onto a rotating video disc. The process is repeated until the final picture to be displayed is assembled on a line-by-line basis on the disc.

Abstract: A depth sounder in which the transducer beam is in the form of a section of hollow cone. With the hollow conical beam, the slant range to the bottom in all directions is the same and minimum depth determination over a path width of 2 to 4 times the depth of the water may be made.

Abstract: Docking sonar uses first and second fan-shaped beams sequentially scanning a target zone in mutually perpendicular directions. Target returns from one beam scan are compared with target returns from the other beam scan and the results are placed into a storage medium such as a video disc and then displayed on a conventional TV monitor, with brightness of the target on the display being an indication of target range.

Abstract: A programmable analog transversal filter is disclosed for processing analog signals and comprising a charge-coupled device (CCD) for receiving a series of discrete analog signals to be delayed by increasing periods and applied to the outputs of the CCD, and a plurality of MNOS memory devices coupled to the taps of the CCD and programmed so that the output of a CCD tap is multiplied by a particular factor. In turn, the outputs of the MNOS memory devices are summed to provide an output signal ##EQU1## where W.sub.k is the weighting factor associated the k.sup.th MNOS memory device. The weighting factors are set into the system by varying the threshold voltage of the corresponding MNOS device.

Abstract: Apparatus which automatically detects targets of interest in line scanned amplitude modulated data systems such as side scan radar or sonar. The apparatus examines a received signal for target highlights followed by a target shadow of a certain length, depending upon range. The apparatus indicates the presence of a target of interest when the highlight-shadow information is contained in multiple sequential signals over a predetermined range window.

Abstract: An array of independent sound cancellation units is arranged over a vibrating noise generating surface. Each unit includes an arrangement of acoustic transducers (sensors) positioned adjacent the surface to obtain an electrical average of the local acoustic noise generated by a predetermined zone of the surface. The summed average is changed in phase and gain by an active filter whose output drives an acoustic projector also positioned adjacent the surface and the acoustic output of which sums with the original noise signal in the acoustic far field, thus tending to cancel the noise. In essence, each vibrating surface zone and its associated sound cancellation unit tend to form an acoustic doublet. A signal indicative of the projector output is used as a feedback signal, with appropriate time delays, to cancel the effect of the projected output signal being picked up by the unit's transducers, and to cancel the effect of the output of other projectors of the array.

Abstract: Apparatus which automatically detects targets of interest in line scanned amplitude modulated data systems such as side scan radar or sonar. The apparatus examines a received signal for certain predetermined parameters. On the basis of values of these parameters a probability code is developed which is a measure of the probability that a target is present. The signal which is divided into a corresponding number of range cells, is rewarded if a target like signal occurs within a certain number of resolution cells of the same range on the next signal. If no target like features are present in this zone on the next signal, a penalty is applied.

Abstract: A multi-path acoustic flow measuring system wherein measured parameters from one path are utilized in the calculation process of another path.

Abstract: The invention provides a transducer for use with a conical reflector in which the transducer comprises a frusto-conical radiating member that is coaxially positioned with respect to the reflector member. The half angles of the radiating member and reflectors are related such that every ray from a selected point of interest on the axis that is reflected from the reflector cone to the active surface of the radiating member intersects substantially normally to the active surface.Where the energy is directed to a point of interest distant from the reflector, the half angles are related in accordance with the formula ##EQU1## ; AND, WHERE THE POINT OF INTEREST IS ON THE AXIS, THE HALF ANGLES ARE RELATED IN ACCORDANCE WITH THE FORMULA ##EQU2## where .phi. = CONICAL REFLECTOR HALF ANGLE;.theta.

Abstract: The beam signals of a multibeam sidelooking sonar system are initially time compressed in a first, relatively low speed, logic section and thereafter transferred to a relatively higher speed logic section for placement onto a video disc. The signals from the video disc are presented to a TV display with the information being portrayed as a moving window. The scan conversion operation may be modified to provide a substantially correct picture geometric format as the vehicle carrying the sidelooking sonar apparatus varies its velocity.

Abstract: Breathing apparatus which incorporates a sensing device operable to adjust the amount of breather's exhaled gas captured in a gas collector section as a direct function of the carbon dioxide content of the exhalation. The amount of exhaled gas captured is sufficiently low in carbon dioxide (CO.sub.2) content to permit rebreathing on the next inhalation, at which time the sensor again adjusts the volume of exhaled gas to be captured. In the one embodiment, a fire fighter's breathing system is described wherein the gas collector section is integral with the breathing mask worn by the fire fighter.

Abstract: Described is a diving helmet which includes a relatively inexpensive adapter unit custom fitted to an individual diver. The assembly includes a standardized helmet body having an inner surface generally conforming to the surface of the adapter unit so as to be capable of being worn by any diver. A sealing arrangement is provided around the base portion of the helmet body and lift off forces are directly communicated to the diver's head.

Abstract: An acoustic imaging system utilizing an acoustic lens and a transducer array. A corrector device is placed in front of the transducer array to flatten the image field so as to conform to the surface of the transducer array.

Abstract: An amplitude modulation envelope detector comprised of a basic voltage doubler envelope detector whose linear dynamic range is increased by a forward bias network and for which the offset voltage is stabilized by temperature drift compensation provided by a temperature compensation network. The forward bias network increases the basic envelope detector linear dynamic range by clamping the basic detector to a predetermined bias voltage which takes the detector components out of the non-linear region of operation, and the temperature compensation network, which is comprised of components matched to those found in the basic envelope detector, stabilizes the offset voltage by providing a signal to the inverting input of an operational amplifier to compensate for the operating characteristic variations of the components in the basic envelope detector and the forward bias network.

Abstract: A circuit for detection of a missing phase voltage condition, and certain other malfunction conditions, in the output of a three-phase A.C. alternator or power supply. Three pulse forming circuits are provided with their input ends each connected to receive a different one of the phase voltages. Each pulse forming circuit provides an output pulse signal for a duration corresponding to the excursion of its corresponding phase signal in a predetermined one of the voltage polarities of the power supply. The outputs of the pulse forming circuits are connected to individual inputs of an OR gate circuit. The OR circuit is adapted to clamp the trigger input of a retriggerable monostable multivibrator to ground during presence of a pulse output from any of the pulse forming circuits. The duration of a triggered output state of the multivibrator is chosen to be greater than the period of alternation of the phase voltages.

Abstract: Described is a diving helmet having receptacles for receiving insertable modular valves or plugs for governing gas flow. The receptacles are diametrically opposed on the helmet and are connected by gas conducting conduits. Gas may be supplied to the diver by way of a main supply duct which discharges the gas against the helmet window for defogging purposes. A sealing arrangement is provided with the diver, and particular valves or plugs are inserted into the receptacles in accordance with a particular gas supply system being utilized.

Abstract: An expendable instrument for determining salinity versus depth in a water column and suitable for use from vessels underway, from helicopters, and from fixed platforms. The salinity indication is obtained by the use of a conductivity cell for measuring the water conductivity, and a standard cell for measuring the conductivity of a standard sample, and obtaining the conductivity ratio. The resultant is transmitted up a wire link to processing equipment.