Abstract: A secure communication system comprising:a first cyclical pseudo-random noise generator comprising determinable vable starting point means and an output;transmitting means for transmitting said pseudo-random noise generator output;receiving means for receiving said transmitting means transmissions, said receiving means having an output;recycling storage means for storing said receiving means output;a second cyclical pseudo-random noise generator identical to said first pseudo-random noise generator having an output and a reset input, said receiving means output connected to said reset input;a correlator having a first input connected to said storage means and a second input connected to said second pseudo-random noise generator output and an output from said correlator; andtiming means connected to said receiving means output and said correlator output for measuring time elapsed between any output of said receiver and said correlator.

Abstract: 1. A helicopter destructor comprising in combination,a hydrophone channel,a microphone channel,a barometer channel,an AND gate connected to the outputs of said hydrophone, microphone, and ometer channels,an explosive means, andmeans connected to the outputs of said hydrophone channel and said AND gate for detonating said explosive means when a trio of signals are simultaneously applied to the respective inputs of said AND gate.

Abstract: 2.

Abstract: A secure sonar communication system for transmitting and receiving intellnce signals within an aqueous medium comprising in combination means for generating an electrical pseudo random noise signal within a predetermined bandwidth, means connected to said pseudo random noise generating means for selectively driving same at one of a plurality of predetermined frequencies, keying oscillator means adapted to selectively produce an output of one of a plurality of predetermined frequency signals, a balanced modulator means coupled to said pseudo random noise signal generating means and said keying oscillator means for mixing the output signals therefrom, bandpass filter means connected to the output of said balanced modulator means for passing the upper sideband thereof, means for receiving an electrical pseudo random noise signal, transducer means, said transducer means being capable of broadcasting acoustical energy upon excitation by the upper sideband from the aforesaid bandpass filter means and in proportion

Abstract: The aerodynamic window is formed of a contiguous pair of gas jet streams driven at subsonic velocity across the entire cross-sectional area of an annular laser beam. One of the jet streams has a shear interface with the interior gas of the laser and has its index of refraction matched to it. The other interfaces with the outside air into which the beam passes and it too has a refraction index matched to the air. Matching of the indices minimizes optical distortion of the beam at the shear interfaces. Distortion produced at the boundary layer of the contiguous jet streams is minimized by equalizing their velocities. To maintain a desired laser cavity pressure, the jet streams are permitted to bend responsively to the pressure differential. The degree of the bending is controlled to reduce window gas consumption.

Abstract: 1. In a submarine simulation sonar beacon adapted for predetermined maneuing under water, a hull having a forward and an aft transducer for receiving an acoustical signal within said water, means disposed in said hull connected to said forward and aft transducers for comparing the time relationship of arrival of said acoustical signal thereat, means coupled to said comparing means for generating an output signal having a characteristic which is a function of said time relationship, means coupled to said generating means for amplitude and highlight modulation of said output signal, and transmitting transducer means mounted on said hull and coupled to said last mentioned means for broadcasting said modulated signal through said water.

Abstract: Laser gas injected into a multiple-pulsed electric discharge laser (EDL) must be removed as quickly as possible following each laser pulse. This `clearing time` can limit the average laser output power. Fast, efficient mass transport is needed and it, in turn, requires the establishment of a uniform velocity flowfield. Such a uniform flowfield can be established by injecting the laser gas through arrays of porous tubes formed with eccentric walls tailored in wall thickness to introduce a non-uniform injection velocity around the circumference of each tube. Preferably, the tubes have a cross-sectional shape formed of displaced circular inner and outer contours to provide a progressively thickening wall. Tailoring is designed to establish an optimum, non-uniform injection velocity distribution capable of producing a nearly irrotational flow that rapidly develops into a uniform flowfield downstream of the tube array.

Abstract: A standard demountable coaxial magnetron has a cathode and a surrounding de shell formed with slots through which electromagnetic energy is coupled into an external resonant stabilizing cavity. The anode and its associated components are contained in a vacuum-sealed interaction cavity envelope separably mounted in the sleeve-like body of the stabilizing cavity. A ceramic window sealably covers the slots and has its axial ends coupled to the axial ends of the anode shell by kovar strips. Since various unwanted modes of oscillation, such as the TE.sub.121 mode, occur in the external resonant cavity, standard mode-suppression TE.sub.121 chokes are used. Such a choke includes a high rf loss absorber carried in a choke cavity formed between the cavity and the anode. However, the kovar strips also extend through this choke cavity and, in many cases, seriously interfere with mode suppression.

Abstract: 1.

Abstract: A linear milling machine adapted to be carried and controlled by a diver nts a hog mill cutter on a frame which itself is secured to the work preferably by a hold-down suction cup arrangement. A driven feed-screw advances the cutter relative to the work. Hydraulic motors drive the cutter and the feed screw as well as a pump used to establish the hold-down power. The suction motor and pump are mounted in a separate oil-filled and pressure-compensated casing. Another small and portable casing provides diver-controlled hydraulic flow regulation for the cutter motor, the feed screw drive and the suction pump motor. By controlling the drive speeds, cuts can be made utilizing only the suction grippers to firmly hold the frame to the work. At the end of each cut, the cutter is manually returned and the suction released to permit the frame to be quickly repositioned and secured for another continuation cut.

Abstract: An extendable infra-red antenna is carried in a bay portion of the aircraft ormally closed by laterally-swinging, clam-shell doors. Separate, unconnected linkage assemblies driven by a common crank extend and retract both the doors and the antenna. When retracted, the antenna linkage is driven into an overcenter disposition but the door linkage is not. As a result, the doors begin to open before the antenna begins to deploy. Conversely, when the antenna is fully extended, its linkage is not overcenter but the door linkage is. The antenna then begins to retract before the doors begin to close. The overcenter relationships cause one member to first move in a direction opposite to that of the other so as to insure against any interference between the moving members. Stop means are provided to permit the antenna to be firmly secured in both its extended and retracted disposition.

Abstract: 1. A generator for producing random binary bits comprising in combination, eans for producing a random noise electrical signal, means coupled to the output of said signal producing means for converting said random noise electrical signal into a variable width square wave signal having polarities proportional to the polarities thereof at any given instant, means connected to the output of said converting means for producing a plurality of constant frequency pulses the number of which is proportional to the widths of those portions of the aforesaid variable width square wave signal having the same polarity, and means effectively connected to said pulse producing means for timely sampling said pulses in terms of binary bits.

Abstract: At least two gas combustion tubes disposed in an end-to-end relationship provide an elongate combustion chamber closed at both ends. A fuel mixture admitted alternatively into each closed end is ignited for generating positive pressure pulses traveling from one end of the chamber to the other. The combustion energy at one end compressed the fuel mixture from the other to permit ignition. A standing wave thus is formed having a pressure anti-node at each of the closed ends. The combustion chamber length is fixed relative to the frequency of the alternating ignitions to produce in the chamber a standing wave having an even number of quarter wave lengths with pressure anti-nodes and velocity nodes at its ends. The wave form thus has a pressure node and velocity anti-node at its mid-point. Combustion gases are discharged at this mid-point to a storage reservoir and, from the reservoir, to the propulsion turbine.

Abstract: A light-walled portable casing, filled with a hydraulic fluid, contains a gh-pressure water pump driven by a hydraulic fluid-driven motor. An externally-carried, suction-type gripper member engages the work object. Pumping evacuated seawater from the engaged surface to establish a secure differential-pressure hold-down force. A pressurized source of hydraulic fluid is applied through the casing to the motor. Fluid discharges from the motor directly into the casing to establish an interior casing pressure that pressure compensates the light-walled structure. Seawater evacuation eventually stalls the motor. When leakage occurs, pumping immediately resumes.

Abstract: An optical system such as an astronomical telescope must be carefully alid to assure that its optical axis is normal to its mounting or support surface. Alignment is achieved by forming circumferentially-spaced diffuse reflectors on the face of the vidicon and by illuminating only these individual reflectors plus a small surface area in their immediate vicinity. Light from the reflectors passes through the optics to a liquid pool for reflection back to the vidicon face plate. If the alignment is true, the reflected images form at fixed locations. In this regard, the locations of the vidicon reflectors are so arranged that the images fall on unilluminated surface areas. Scanning then detects both the reflectors (dark on bright) and the images (bright on dark). Deviations from the fixed image locations represent misalignments which can be corrected.

Abstract: The present meter is characterized by its very accurate cosine response to urrent vector components of fluid (air or water) velocity parallel to the rotational axes of its propeller-like flow sensors. Structurally, it employs two flow sensors rotatably mounted on a rod or `sting` carried by a casing. Each sensor includes a pair of back-to-back propellers or fans mounted on a single axial shaft rotatably supported by the rod. The rotational axes of the two flow sensors are normal one to the other and also normal to the axis of the rod. Rotation of the fans activates a switch-like arrangement electrically coupled to an up-down counter carried in the casing. Blade rotation in one direction yields an `up` count and vice versa.

Abstract: Most Diazo printers and other such copy machines have an automatic feed capability provided by a drive roller for receiving light-sensitive paper from copy paper rolls of varying widths and feeding the paper into the machine. To provide a square footage count of the machine output, a measuring wheel is mounted to ride on the drive roller and be driven by its contact with the copy paper. The wheel roller which carries a small magnet is disposed closely adjacent to a magnetic switch so that, once during each roller revolution, the magnet closes the switch and closes a power circuit coupled to a counter. The diameter or circumference of the wheel roller is preselected so that each of its revolutions represents one square foot of the copy paper on which it rides. Preferably, there are provided a plurality of wheel rollers each of which has a diameter matching that of various copy paper widths for which the machine is adapted.

Abstract: The transducer's active elements are a plurality of thin, narrow, piezoelric bars bonded side-by-side to a flexible plate. Electrically, a circuit is coupled across the thickness of each bar or strip to include the bars as a plurality of parallel capacitors. The plate has a fixed length that is maintained during operation. Consequently, piezoelectric length expansions and contractions of the bars are translated into an oscillating bending motion of the bars and the plate for transducing purposes.

Abstract: Four microphones are disposed one at each corner of a square or rectangular onfiguration located near a base station from which the lightning distance is to be measured. A light detector also is located near the base station. When lightning occurs, the light and sound waves are detected and passed in pulse form over separate channels to a computer. The time intervals between lightning and sound in each channel are measured, stored and used to calculate the slant range distance of each microphone from the lightning event. Using the slant range distance values and the known spacing values of the rectangular configuration, a computer provides the desired distance value which, for present purposes, is the horizontal distance of the closest microphone to a ground point perpendicularly beneath the lightning event. The azimuth of the ground point from the closest microphone can be determined by a simple calculation using the ground point distance value.

Abstract: Lasing can be achieved by pumping a laser cell containing a vapor formed predominantly of Group VI dimers such as S.sub.2, Te.sub.2, Se.sub.2, TeO, TeSe, TeS and SeS, from a ground electronic state to a selected vibrational-rotational level in a selected excited electronic state. The selected excited electronic state is one having allowed transitions relative to the ground electronic state and the selected level of the excited state is one that is below the dissociation limit of that state. Lasing transitions then occur between the selected excited state level and higher vibrational-rotational levels of the ground state. For example, lasing is achieved at S.sub.2 (B-X) and at Te.sub.2 (A-X).