Abstract: A method and apparatus for calibrating laser Doppler velocimeters having one or more intersecting beam pairs. These velocimeters measure fluid velocity by observing the light scattered by particles in the fluid stream. Moving fluid particulates are simulated by fine taut wires that are radially mounted on a disk that is rotated at a known velocity. The laser beam intersection locus is first aimed at the very center of the disk and then the disk is translated so that the locus is swept by the rotating wires. The radial distance traversed is precisely measured so that the velocity of the wires (pseudo particles) may be calculated.

Abstract: An interface permits bi-directional data signal transfer between the microcomputer of the receiver and an addressable controller-decoder designed for use in conjunction therewith. The data transfer permits expansion of the receiver functions and future adaptability to a variety of satellite services. The interface transfers messages from the microcomputer representing keystrokes received from the receiver keyboard and the status of the various receiver components and receives commands from the decoder for regulating the operation of the receiver components and for the transfer of specific information. The data transfer is achieved through a serial communication protocol which facilitates the interaction between units.

Abstract: A secure cable television distribution system is disclosed for controlling subscriber access to preferred channel information in accordance with the teachings of the instant invention. Premium channel information to be selectively provided to a subscriber is tapped from the transmission medium, modulated, inverted and separated into discrete channel signals. The discrete channel signals are then selectively reintroduced to the transmission medium to effect cancellation of premium channel information which is not to be provided to a predetermined subscriber.

Abstract: A method and apparatus for scrambling a composite television signal and method and apparatus for unscrambling of the scrambled television signal are disclosed in the present application. The method of scrambling shifts at least some lines of video information relative to adjacent (preceding or subsequent) lines of video information according to a predetermined scheme, and deletes at least some portions of the signal which comprise synchronization or control information of a known or predetermined repetitive form from between at least some of the adjacent shifted lines of video information. The method of unscrambling applies a complementary shift to return the video information into proper time spacing and includes the insertion of any necessary synchronization information eliminated from the signal during scrambling. Timing information allows the unscrambler to reverse the scrambling operation and thereafter insert any necessary synchronization information.

Abstract: A non-retro angle of arrival meter in which reflection means are mounted ative to an aperture and to detectors for radiation such that radiation passing through the aperture is reflected from the reflection means to the detectors to cause signals to be produced at the detectors that can be processed by a processor for recording these signals and determining the direction from which the radiation is originating.

Abstract: Apparatus for measuring the velocity of a moving image or object including a first array of sensors extending in a first direction transverse to image motion for sensing a primary set of image elements; a second array of sensors extending generally in the first direction and spaced a known distance from the first array for sensing successive sets of image elements; a device for correlating the primary set of image elements with each of the successive sets of image elements and for producing a correlation level indicating the level of correlation of the primary set with each of the successive sets; means for selecting one of the correlation levels which indicates an optimal level of correlation; and means for determining the time interval between the sensing of the first array of the primary set and the sensing by the second array of the successive set corresponding to the selected correlation level; in addition, the means for correlating may include means for comparing with the primary set each successive set

Abstract: In a laser-doppler-anemometer two frequency-displaced partial beams are transmitted from a transmitted device including a laser to a measuring probe positioned at a remote measuring volume by means of a polarization-direction-preserving optical "single-mode" fiber with two orthogonal principal axes, the transmitter including a member for turning the polarization direction of one partial beam by 90.degree., and the measuring probe including another polarization-direction-turning member for re-establishing the original coincidence between the polarization directions of the two partial beams. The transmitting device may thus be positioned at a distance from the measuring volume while the measuring probe may be designed with small physical.

Abstract: Television or similar picture scrambling or the like wherein narrow trapping of the visual carrier is effected with one-direction FSK-FM modulated wobbulation of the visual carrier, preferably alternately at different multiples of the horizontal synchronizing frequency.

Abstract: An addressable subscription television decoder includes an input stage including an IF amplifier for converting a scrambled RF television signal to a composite baseband video signal. The baseband video signal comprises either a nominal sync component or a sync component having suppressed horizontal sync pulses during video fields and having non-suppressed sync pulses during vertical intervals, the vertical intervals also including selected encoded data signals. An AGC voltage for controlling the gain of the IF amplifier is developed by a circuit exhibiting a relatively short time constant whenever the composite baseband video signal is characterized by nominal level sync pulses, the time constant being increased in response to suppressed horizontal sync pulses. The sync pulses produced during the vertical intervals of the composite baseband video signal are thereby not subjected to excessive IF gain for facilitating processing of the data signals by the decoder.