Abstract: The velocity and change in velocity of a rotating or otherwise moving surface is measured by a laser Doppler technique. In particular, a diffraction grating is formed on the moving surface either by machining processes or by affixing a ready-made grating thereto. The grating surface exhibits periodicity in one or more directions, either separately or simultaneously. The presence of the grating produces Bragg order diffraction reflections at specific angles relative to the surface. These Bragg order reflections contain information, in the form of Doppler shifts, concerning the motion of the surface and the body to which it is attached. This Bragg order Doppler shift information is readily analyzable using conventional signal processing apparatus and processes to produce the desired velocity and torsional vibration information.

Abstract: In a cable television system of the type wherein a cable television signal including free and restricted television channels is subjected to selective frequency conversion at individual terminal units to obtain a desired one of the channels for observation, a signal detector is provided for detecting the presence or absence of a polling signal from the central facility and the frequency converter is either disabled or adjusted for reception of a free channel if no polling signal is received.

Abstract: A method of visually representing output data on a screen by deflecting a laser beam in both horizontal and vertical directions for scanning, and an indicating device for performing the above method. The laser beam is first divided into two polarized waves which are, after being modulated in accordance with the output data, combined into a first synthesized laser beam. The two polarized waves are alternately extinguished synchronously with a predetermined simple harmonic oscillation. The synthesized laser beam is then horizontally deflected by means of a sinusoidally oscillating mirror so that the angular displacement of the deflection oscillates in synchronism with the predetermined simple harmonic oscillation. The resultant deflected beam is again divided into two polarized waves, one of which is then inverted. The resulting two polarized waves are combined to obtain a second synthesized laser beam whose angular displacement in deflection is unidirectional at any phase.

Abstract: A laser pulse is injected into an unstable ring resonator-amplifier structure. Inside this resonator the laser pulse is amplified, spatially filtered and magnified. The laser pulse is recirculated in the resonator, being amplified, filtered and magnified on each pass. The magnification is chosen so that the beam passes through the amplifier in concentric non-overlapping regions similar to a single pass MOPA. After a number of passes around the ring resonator the laser pulse is spatially large enough to exit the ring resonator system by passing around an output mirror.

Abstract: Apparatus for scrambling and descrambling the video portion of TV signals is disclosed. The video portion of the TV signal is stored in a serial memory such as a charge coupled device. Scrambling is accomplished by shifting the end portion of the lines of video to the beginning by recirculating the data stored in the charge coupled devices for a portion of a line of the video signal. Two charge coupled devices are provided so that when the data stored in one device is being recirculated for scrambling the subsequent line can be stored in a second device. Descrambling is an inverse operation and is accomplished in essentially identical hardware.

Abstract: A method of modulating the output of a solid state diode laser by directly straining the laser chip. The chip is mechanically coupled to a transducer such as a piezoelectric crystal in such a manner that a dimensional variation in the transducer is translated into a corresponding variation in the chip. It is contemplated that the modulated output will have application in communication systems and in particular a hydrophone system.

Abstract: A variable area recording geometry is formed over the surface of a photosensitive material by scanning and exposing with an optical writing beam. The width of this area is determined by input signals to be processed. The exposed photorefractive medium results in a phase modulation of an optical beam traversing the medium in a direction parallel to the surface as in an integrated optical waveguide.

Abstract: An electrical circuit that interrupts normal operation of a cable television channel selection box responsive to unauthorized entry into the box. A closure means is mounted about its periphery by a plurality of screw members that must be removed in a predetermined sequence to avoid disabling the box. A power source provides current through a bypass means in the form of a normally closed switch means as long as the closure means remains closed, but removal of a fastening means not associated with said bypass means prior to interruption of said current results in de-activation of the channel selection box.

Abstract: In an integrated laser/FLIR rangefinder a scanner position sensor comprising an LED of the array of LEDs of a forward looking infrared (FLIR) system, a reticle grating located at the image plane of LED optical path, and a silicon detector positioned to receive the light passing through the reticle grating for producing a plurality of signals in response to light passing through each grating slot. One of the signals is selected for the synchronization logic for controlling the charging and firing of the laser. If there is no range return a second signal is selected for adjusting the position of the timing pulse.

Abstract: A method for scrambling and descrambling television programs in which the horizontal synchronizing information is suppressed at a CATV supplier's head-end and then regenerated at the subscriber's converter. The pulse frequency is multiplied by a factor N/M, in which N and M are integers thereby generating a synthesized pulse stream which is, in turn, encoded with data identifying the values for N and M. This encoded pulse stream is modulated onto the audio subcarrier wave in the TV video signal and transmitted to the converter. The converter then demodulates and recovers the encoded pulse stream, decodes the same to recover the identifying data, using this data to obtain the correct values for N and M which have been transmitted separately on a digital data channel. The converter then multiplies the synthesized pulse stream by M/N regenerating the horizontal synchronizing pulse stream and inserts the same into the TV video signal at the proper phase.

Abstract: In order to determine the distance of a target, illuminated by a remote pulsed laser, from a nearby observation point, the time interval between the arrivals of a direct laser pulse and of a reflection of the same pulse from the target is measured along with the angle included between the two directions of incidence. From these data the target distance can be calculated with reasonable accuracy, e.g. for the purpose of emitting an alarm signal if the calculated distance lies within a predetermined range. The device implementing this procedure could also be used in a feedback loop of a system for the automatic pointing of a pulsed laser beam.

Abstract: A surveillance radar system comprising an omni-directional transmitter and a number of radar receivers located at different geographic locations from the transmitter which are capable of resolving the angular location of targets by using antenna lobe multiples over the range to be monitored so that anti-range missiles cannot destroy the receivers since their locations will be unknown. The transmitter transmits on a continuous basis rather than on pulsed basis to reduce the probability of location by anti-radar missiles.

Abstract: A range determination apparatus for determining target range within a range depth of D and within a range bin error of e comprises a carrier frequency transmitter for transmitting a carrier frequency and a generator for generating at least two modulating signals having frequency f.sub.1 and f.sub.2, respectively. A modulation device, operative for at least two discrete frequencies for providing one of simultaneous or sequential modulated signals, is coupled to the carrier frequency transmitter for modulating the carrier. The two modulating frequencies and a common sub-multiple counting frequency are related such that f.sub.o =m.sub.1.sup.' f.sub.1 =m.sub.2.sup.' f.sub.2. A receiver is provided for receiving a reflected signal from the target and for producing a corresponding received electrical signal. A phase detection device is responsive to the modulating signals of the generator and the received signals for detecting the phase difference x.sub.1.sup.' and x.sub.2.sup.

Abstract: The multiple measuring control volume laser Doppler anemometer includes a laser for providing an optical beam. The beam is transformed by an optical arrangement to produce a number V of measuring control volumes wherein each control volume has two focussed optical beams intersecting at a unique predetermined angle .phi.. A detector collects the scattered light from the measuring control volumes in order to determine the velocity at each of the control volumes.

Abstract: An addressable cable television control system controls television program and data signal transmission from a central station to a plurality of user stations. The data signals include both control and text signals in video line format which are inserted on the vertical interval of the television signals, thereby freeing all channels for transmission of both television and data signals. Moreover, full-channel teletext data in video line format may be transmitted on dedicated text channels with the modification of only head end processors. An intelligent converter at each remote user location uses the data signals to control access to the system on the basis of channel, tier of service, special event and program subject matter. The converter uses a graphics display generator to generate display signals for the presentation of the text data on the television receiver and for the generation of predetermined messages for the viewer concerning access, emergencies and other functions.

Abstract: Methods and apparatus for scrambling and unscrambling a plurality of data streams having differing data, on a plurality of signal channels, are taught. The data streams may be television programs or other signal information, transmitted in a frame-by-frame manner with discrete synchronizing information, and where some of the data streams may be high priority such as pay-TV program material. All of the data streams are synchronized, an encryption key code is imposed on them, and a data package containing an identifier code for each data stream and a routing code is generated, so that each data stream is assigned at any instant of time to a specific one of the plurality of signal channels. The data package is encrypted in each data stream by being inserted at a specific place therein relative to the synchronizing information.

Abstract: A system is described for measuring the distance to an object by comparing a first component (18) of a light pulse that is reflected off the object (14), with a second component (20) of the light pulse that passes along a reference path (26) of known length, which provides great accuracy with a relatively simple and rugged design. The reference path (26) can be changed in precise steps so that is has an equivalent length approximately equal to the path length of the light pulse component that is reflected from the object. The resulting small difference in path lengths can be precisely determined by directing the light pulse components into opposite ends of a detector (70) formed of a material that emits a second harmonic light output at the locations where the opposite-going pulses pass simultaneously across one another.

Abstract: A high power amplifier for amplifying millimeter-wave radiation comprising: a length of metallic waveguide tapered from a small cross-sectional end to a larger cross-sectional end; a magnetron-type electron injection gun for injecting a spiral beam of relativistic electrons at the small end of the waveguide for propagation axially therein so that the wall radius of the tapered waveguide increases in the downstream direction of the electron beam; an input coupler for launching electromagnetic waves to be amplified into the waveguide at the large waveguide end thereof such that the individual frequencies in the input waves are reflected at various points along the constriction of the waveguide taper so that they copropagate with and are amplified by the electron beam; and a magnetic circuit for generating an axial magnetic field within the tapered waveguide with a unique profile approximately in accordance with the following equation to maintain synchronism: ##EQU1## where the z subscript is the waveguide axial

Abstract: In a subscription television system, only a video signal for a specific program is scrambled in a television signal in accordance with a predetermined scrambling mode. A key signal, used for unscrambling the scrambled video signal, is generated in response to the scrambling mode. The key signal is transmitted after the scrambled program.

Abstract: In the disclosed measuring device, a projecting arrangement projects radiation modulated at a predetermined frequency toward an object and a sensing arrangement senses the radiation reflected by and coming from the object for producing an output signal indicative of the energy intensity of the received radiation. The projecting arrangement and sensing arrangement are moved relative to each other to scan the object while a converter converts the output signal of the sensing arrangement into digital data in synchronism with the modulation of the radiation being projected by the projection arrangement. The digital data is processed each predetermined number of cycles for producing an electrical output related to the change in energy intensity of the reflected radiation.