Abstract: In order to replace acoustic lenses, frequency units corresponding to frequencies used by the acoustic lenses and housing transmitted pulse generating means, circulators and receiving means can be selected and the signal of a gate opening at a timing at which ultrasonic waves of a sample return can be selected.
Abstract: Laser telemetry and Doppler measurement apparatus using pulse compression has a transmitter for providing a periodic pulsed transmission laser wave having a pair of pulses, one pulse being frequency modulated on one side of a main frequency F.sub.E, and the other pulse being frequency modulated on the other side of the main frequency F.sub.E. The transmitter also provides a reference laser wave having a frequency F.sub.L. A photomixer is adapted for superheterodyne reception of the reference laser wave and a return laser signal which has been reflected from a target. The return laser signal has a Doppler shift frequency F.sub.D. The photomixer provides a beat signal having a frequency F.sub.I plus F.sub.D, where F.sub.I is an intermediate frequency. A Doppler aquisition loop transposes the beat signal frequency and provides a transposed signal to compensate for the Doppler shift. The Doppler acquisition loop provides a coarse compensation signal having a frequency near the frequency F.sub.D.
March 26, 1984
Date of Patent:
May 10, 1988
Georges Arnaud, Leon P. Robin, Jean L. Meyzonnette, Bertrand Remy
Abstract: An apparatus for displaying ultrasonic images picked-up by an ultrasonic microscope including a digital scan converter having three image memories for storing successively picked-up three ultrasonic images. The digital scan converter functions to reconstruct a color image from the three ultrasonic images by simultaneously reading ultrasonic image signals out of the image memories as red, green and blue color signals.
Abstract: Programming tiers are authorized for viewing on an impulse pay-per-view basis. The system operator controls individual receiver units to block the display of programming on selected tiers because the subscriber finds the content of same objectionable or to prevent members of the household from incurring charges without the subscriber's consent. The broadcast signal includes portions addressable to particular receiver units. These portions include a designation of tiers to be blocked and a command to store same in the unit memory. Upon command to display a program on a selected tier, the memory is accessed and the stored designation compared with the selected tier. Receivers having stored designations corresponding to the selected tier are unable to display the program.
Abstract: A television converter includes a circuit for detecting scrambled signals and enabling the descrambler in response thereto. Scrambled signals are detected by sensing amplitude modulated digital tag information on the audio carrier. The descrambler is enabled if amplitude modulation is detected on the audio carrier during the portion of a horizontal line where digital information is expected, and also if no amplitude modulation is detected during a portion of the horizontal line where no data is expected. The scrambled signal detector of the present invention reduces the tendency for noise and other influences to enable the scrambler when viewing a clear, i.e. unscrambled, signal.
Abstract: An apparatus and method for determining aircraft position and velocity is disclosed. The system includes two CCD sensors which take overlapping front and back radiant energy images of front and back overlapping areas of the earth's surface. A signal processing unit digitizers and deblurs the data that comprise each image. The overlapping first and second front images are then processed to determine the longitudinal and lateral relative image position shifts that produce the maximum degree of correlation between them. The signal processing unit then compares the first and second back overlapping images to find the longitudinal and lateral relative image position shifts necessary to maximize the degree of correlation between those two images. Various correlation techniques, including classical correlation, differencing correlation, zero-mean correction, normalization, windowing, and parallel processing are disclosed for determining the relative image position shift signals between the two overlapping images.
June 14, 1984
Date of Patent:
June 9, 1987
Crane Co. (Hydro-Aire Division)
Edgar A. Hirzel, Douglas M. Longyear, Jr.
Abstract: A moving body measuring instrument is disclosed which projects, from predetermined locations thereof, a plurality of beams of light at predetermined angles into a same plane, receives, at predetermined locations thereof, the beams reflected from a moving body as it moves to intersect with the beams, calculates parameters of the motion of the moving body in accordance with predetermined operation from timing data of the beams received, and indicates the results of the calculations on an indicator. The moving body has a light reflective member provided thereon which reflects a beam for measurement toward a direction incident thereto irrespective of its incident angle, and substantially same locations are provided at which beams are projected and received.
Abstract: A jamming circuit for a CATV system in which the jamming signal is offset in frequency by a voltage controlled oscillator and then mixed with the unjammed television signal. A difference component is obtained from the mixer and is attenuated to a fixed level. This signal is then 100%-AM-modulated by a low frequency signal. The AM-modulated signal is mixed with an output from the voltage controlled oscillator and the double side bands are superimposed on the television line feeding the terminal of the subscriber.
Abstract: In a television receiver for a transmission system in which the video signal is scrambled to allow only for its authorized reception, a video signal processor (8) is provided in which the scrambled video signal is de-scrambled. A low rate control data signal present at an output (11) of a sound/data signal processor (10) is employed to periodically set (say once every one or two seconds) a master pseudo random pulse generator (12B) producing an output of pseudo random configuration at frame rate which is used to periodically set a video slave pseudo random pulse generator (15) to produce an output of pseudo random configuration at line frequency. This is applied to an input S of the processor (9) and forms the scrambling key for the line-by-line de-scrambling of the video signal.
Abstract: Of the scrambling systems used in CATV and direct satellite broadcasting systems, the invention pertains to the transmission of a keying signal for demodulation. The keying signal, as a carrier wave displaced 90.degree. in phase from a picture carrier wave, is superimposed on the conventional sync signal suppression period with no sound carrier wave being processed, thereby avoiding the generation of buzzing noise which would occur when the keying signal is superimposed on the sound carrier wave. With this invention, not only can the generation of buzzing noises be eliminated, but also even in multiplex sound systems the sound signal can be transmitted without the sound quality being adversely affected. Also, no synchronizing signal can readily and easily be detected and, therefore, subscription TV programs can not be viewed by unauthorized persons.
December 13, 1984
Date of Patent:
January 27, 1987
Matsushita Electric Industrial Co., Ltd.
Abstract: Apparatus restricts access to a communication network having at least one service node for providing services to subscribers. A subscriber terminal, coupled to the communication network, includes a secret node key. A succession of frame verifier (FV) codes, derived through the use of the secret node key, is generated and transmitted on the network. A network access controller (NAC), coupled to the network, includes a record of the secret node key and uses the key to encrypt a seed which is transmitted to the subscriber terminal for use in generating the FV codes. The NAC also independently computes the succession of FV codes which should be generated by the subscriber terminal. A distributed access controller (DAC), coupled to the communication network, includes a look-up table for storing the succession of FV codes computed by the NAC. The FV codes transmitted by the subscriber terminal are detected and compared to those stored in the look-up table.
Abstract: A television signal receiving system for use with a scrambled television signal or a standard television signal includes a recording and reproducing circuit which records and reproduces the received television signal and a monitor for displaying the received or reproduced television signal. A descrambling circuit descrambles the scrambled television signal either as received or reproduced to generate a descrambled television signal when a detector detects the existence of a scrambled television signal and generates a control signal in response thereto. A switch responds to the control signal and automatically supplies to the monitor either the descrambled television signal or the standard television signal according to the type of television signal being received or reproduced.
Abstract: An optical radar system for vehicles has a stationary receiver and a transmitter which scans the road surface ahead of the vehicle, the scan area being shifted in accordance with the direction of steering of the vehicle. The scan area is covered by periodically sweeping a narrow-beam pulse laser through the designated scan area and monitoring the return lag of pulses reflected by objects in the scan area. The scan area is centered over the longitudinal axis of the vehicle while the latter is moving straight ahead. The axis of the scan area is shifted in proportion to the orientation of the steering wheel of the vehicle.
Abstract: An encrypted video distribution system includes a signal-originating head end for scrambling the audio portion of outgoing television program-bearing signals. In particular, the audio content of a television program alternately reverses polarity under control of a keyed pseudo random generator. At each authorized subscriber location, a pseudo random generator is included in receiver descrambling circuitry and operates in a sequence identical to the like circuit at the head end to restore the polarity-inverted audio signal, thereby permitting reception and presentation of intelligible audio subject matter.In accordance with another aspect of the present invention, the video information present during selected lines is inverted about a predetermined inversion level and restored at equipped, authorized subscriber stations also under control of the pseudo random generators.
Abstract: A method for scrambling a television signal for use with a multiplexed analog component (MAC) format employs a three digital bit code for each horizontal line of the picture. The bits identify the position of the luminance and chrominance information of the signal for every line of the television picture and whether the information is to be scanned from left to right or right to left.
Abstract: A combined sun and star sensing system for attitude and position control of a space vehicle, includes a star image sensor having a first objective and a first detector array arranged in the focal plane, the objective being constructed for a well defined aberration so as to convert a point like object into a defined spot or area having a diameter larger than the diameter of an element of the detector array; the sun sensor has a regular objective and a second detector array is arranged in the image plane of that objective sun sensor; the two detector arrays have similar and a similar number of detector elements, and are alternately connected to a single evaluating electronic.
Abstract: A digital code reader reads the digital key code in a scrambled video signal. The key code represents the scheme used to scramble the signal before broadcasting and is used by the video receiver to unscramble the received signal. To prevent misreading of the key code due to interference such as ghost signals, the reader uses a predetermined property established for the broadcast signal. The change in that property caused by interference in the received signal is determined and a control signal is generated from that determination. A threshold signal is used to reproduce the key code from the received signal by comparison of the levels of the received signal with the level of the threshold signal. The level of the threshold signal is set by the control signal, which depends on the change detected in the predetermined property of the broadcast signal. Thus the level of the threshold signal can be set to enable the reproduced digital information to match the broadcast digital information.
Abstract: A video signal is encoded prior to broadcasting by inverting portions of the signal about an encoding axis at a predetermined reference level. To enable the reference level to be determined accurately after the received signal has been recorded and played back using a VTR having a noise reduction circuit, two identification signals having the same level are included in two consecutive horizontal periods of the signal, respectively. The level of the identification signal in the second horizontal period is unaffected by the noise reduction circuit. A decoding circuit detects the level of that identification signal and uses it to generate a decoding axis having the reference level. The decoding circuit at the receiver is thus able to accurately restore the encoded signal by reinverting the inverted portions about a decoding axis having the same level as the encoding axis.
Abstract: A subscriber cable television system using predominantly digital signal processing techniques employs an improved time-warp and segment scrambling method for providing extremely high security. Means are also disclosed for suppressing the undesirable effects of discontinuities in the scrambled video signal by methods of inserting additional data samples between adjacent continuous segments, and by dithering the video line positions of the discontinuities. Preferably the scrambler and descrambler each have a memory for storing video samples, first and second address counters for providing read and write addresses to the memory, and means for decrementing or inhibiting address counting during the time between segments of continuous video samples in order to insert and delete samples during scrambling and descrambling, respectively.
Abstract: An optical alignment sensor capable of receiving radiation from a collima light source and subsequently providing orientation attitude and alignment data. Collimated light from the source impinges an aperture plate causing a shadow of the aperture plate pattern to fall across a two-dimensional photodetector array. Since the aperture pattern is larger than the active area of the array, only a portion of the light spots forming the aperture plate pattern will fall on the array. By varying the spacing of the apertures in the aperture plate in a known way, the light spots on the array can be associated with specific apertures in the aperture plate. From the location of specific light spots on the array, the angular orientation of the alignment sensor may be determined with respect to the incident beam.
January 3, 1984
Date of Patent:
January 6, 1987
The United States of America as represented by the Secretary of the Navy