Abstract: A secure audio channel transmission system method and apparatus in which an FM signal is generated on an FM broadcast frequency, such as 107.5 megahertz, divided in frequency by 2 and distributed via a cable television system to subscribers equipped with frequency doubler circuits that reconstitute the FM signal for reception on a standard FM broadcast receiver. Unauthorized reception is prevented by the use of the non-standard, frequency-divided signal which is not receivable by standard broadcast channel television or FM receivers.

Abstract: An apparatus for the early detection of oncoming wind shear, without false indications arising through turbulence. A forward looking laser speed sensor (11) provides a signal (12) containing information on air velocity over a range of distances about a measurement distance (X). This is subject to spectrum analysis (15), to identify all velocities present in a time sample of the signal (12). These velocities are further processed (17) to establish the air velocity at substantially the measurement distance (X), and the highest and lowest velocities present over a distance range (L). A time sequence of results is combined to provide a wind shear hazard level for comparison with a hazard level limit computed (13) from the prevailing conditions.

Abstract: A system for measuring the relative orientation between two objects. A transmitter/receiver assembly on one of the objects transmits a beam of monochromatic light to a Ronchi-type retro-grating disposed on the other object. The grating reflects the light back to one or more charge transfer device area arrays in the transmitter/receiver assembly which provides orientation data to a computer which determines relative pitch, yaw and roll between the two objects.

Abstract: A distance measuring apparatus provided with a plurality of light-emitting units and a plurality of light-receiving units. The light emission period of each of the light-emitting units is changed over at each predetermined period interval. A plurality of light-receiving elements constituting each light-receiving unit are constructed so as to receive the reflected light from a plurality of distance measurement fields of view on an object to be photographed in a plurality of distance measurement zones obtained by dividing a range to be measured into several blocks. The input signal from each of the light-receiving elements in each of the distance measurement zones is changed over in synchronism with the light emission period of the light-emitting units and the output signals for the respective distance measurement zones are compared, whereby a distance data indicative of the distance measurement zone most approximate to the object distance is put out.

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: A sine wave modulator for decoding a sine wave encoded television signal includes a passive attenuation network comprising a pi-arrangement of PIN diodes. The encoded signal is supplied to the input port and the decoded signal is taken from the output port. A common bias arrangement for the series-shunt-connected PIN diodes results in the impedance of one PIN diode changing oppositely to the impedance of the other PIN diodes such that the impedance presented to the input and output ports remains substantially constant.

Abstract: A laser beam modulating method is characterized in that the distribution of power density of the laser beam is changed by closing and opening a passage for the laser beam from a laser resonator. An apparatus for carrying out the method includes a modulator for opening and closing the passage for the laser beam from the laser resonator to a laser processing head assembly.

Abstract: A system is disclosed for encoding and decoding the audio signal portion of a television signal to prevent unauthorized reception of the audio signal. At the encoding stage, the audio signal is applied to a multiplier which combines the audio signal with a programmable carrier having a frequency controlled by a frequency selection protocol to produce an output signal which is spectrally inverted from the original audio signal. The spectrally inverted signal from the multiplier is applied to a sideband filter which filters out the upper sideband of the spectrally inverted signal to produce an encoded signal having the same bandwidth as that of the original audio signal. At the decoding stage, the carrier signal is phase-shifted to compensate for phase delay imparted to the encoded signal in the encoding process and combined with the encoded signal to decode the encoded signal.

Abstract: Light projected from an active lighting means to an object is reflected by the object, and a light spot is produced on a light-sensitive element by the light reflected from the object. The distance to the object is determined by detecting the position of the light spot on the light-sensitive element.The light-sensitive element for receiving the reflected light from the object has formed on a portion of a surface thereof an insensitive zone which has the same width or the same area as the light image produced by the reflected light and the light-sensitive element moves on an image plane in a certain relationship with the distance to the object whereby a change in a photoelectric output of the light-sensitive element is detected to detect the distance to the object.

Abstract: An apparatus to evaluate objectively the concentration and motility of particles suspended in a sample of liquid, and particularly to an apparatus to solve objectively the problem of evaluating these important characteristics in a very simple manner and in a short time by exploiting the Doppler effect. The sample to be examined is subjected to one of the two sub-beams resulting from the suitable division of a coherent monochromatic light beam emitted by a polarized LASER, while the other sub-beam is considered as a reference light sub-beam. Because of the very little difference between the frequencies of the original and scattered light a beat is originated in the rejoined two sub-beams which is dependent on the characteristics of the examined sample.

Abstract: A wireless subscription television system arranged to transmit ciphered video signals from a transmitter to receivers in which the transmitting system comprises an enable code setting means, a transmitting means for transmitting control signals to allow a respective enable code of a receiving system to be picked up and a converting means for masking said enable codes and sending out masked enable codes, and on the other hand, the receiving system has a plurality of decoder systems each comprising a key code input means, a means for picking up a key code put in by the input means after converting it into an enable code by means of the control signals and a comparator means for determining if the picked-up enable code and the enable code as masked sent from the transmitting system are same or not. Thus, when the both enable codes come to be same, the respective decoder system is set in receivable condition.

Abstract: A poach-resistant system enabling cable television subscribers to receive upon request certain programs otherwise unavailable (i.e., "secure") while precluding such reception by non-requesting subscribers as well as non-subscribers. Before transmission of such a secure program the roster of subscribers is scanned at a central control station having complied subscribers' requests for that program, and a resulting string of pulses corresponding in sequence to the respective subscribers is punctuated with program command pulses timed to designate those subscribers who have requested the program. Transmission of the resultant program command signal string over the cable to junctions with leads to the respective subscribers' television sets results in unblocking of such junction for each of the requesting subscribers only. Allocation of plural clocking pulses to each subscriber enables program availability to be tiered as desired.

Abstract: A method and system for measuring relative speed of a ship through a body of water with improved accuracy and simplicity. It employs a free floating buoy and a pair of tracking scopes. The buoy is launched and tracked by the scopes with electronic circuit arrangements so that the time of relative movement of the buoy between transverse positions opposite the scopes is accurately measured.

Abstract: A video signal is scrambled by partitioning the signal into blocks of segments, reversing the sequence of segments in each block, randomly delaying the reversed segments and reversing the sequence of the randomly delayed segments. The double reversal of the block segment sequence results in a scrambled signal of high security but which may be unscrambled by a decoder having a complementary random delay characteristic and a total segment storage capacity which is less than that of the scrambler and also less than the maximum line-to-line interchange of the segments within each block. Selection of segment lengths provides inter-line or intra-line block scrambling.

Abstract: The present invention relates to an improved Schottky barrier device wherein the leakage current present in the reverse bias mode attributed to the presence of an electric field at the Schottky barrier (18) is significantly reduced by the inclusion of one or more field shields (22), P.sup.+ -type diffusions located under the metal anode (16) of the Schottky barrier device at the Schottky barrier (18). The P.sup.+ -type field shields, which are disposed in a pattern on the surface of the Schottky barrier, reduce the surface electric field present, thereby significantly reducing the leakage current related thereto.

Abstract: In a copier with a copying platen, and platen cover unit pivotal thereover, which may comprise a document feeder, the platen cover unit having connecting pivotal lifting means, and a magnetic latch for magnetically latching the platen cover unit in a closed position closely overlying the copier platen with a magnetic flux field between the platen cover unit and the copier generated by at least one magnet on one completing a magnetic circuit through at least one magnetic flux conductive member on the other when the magnetic latch is closed, the magnetic latching of the platen cover unit in the closed position providing for document retention and illumination thereunder and magnetic resistance to opening of the platen cover unit by the lifting means, and with a switch for indicating closure of the platen cover unit, the improvement wherein the switch comprises a magnetic switch magnetically coupled to the magnetic latch, the magnetic switch being magnetically actuated in response to the change in magnetic flux

Abstract: An electronic phase shifter for shifting the phase of a sine wave at an input terminal, as measured at an output terminal, without affecting the magnitude thereof and having the ability to operate over a wide range of input voltages is disclosed. The electronic phase shifter comprises, inter alia, an operational amplifier and a unique variable output resistance device. A control signal, in the form of a current, for controlling the phase shift of the sine wave is applied to the input of the variable output resistance device. Buffering of the electronic phase shifter from preceding stages is controlled by matched resistors operatively connected between its output and input terminals and the inverting input terminal of the operational amplifier. The operating frequency range of the electronic phase shifter, and, accordingly, the phase shift range, is controlled by a capacitor connected from its input terminal to the non-inverting input terminal of the operational amplifier.

Abstract: The present invention is a method for improved mud pulse telemetry. Mud pulse signals generated by a downhole mud pulser are detected at the surface by monitoring mud flow rate. Mud flow rate can be monitored by use of a flow meter placed downstream from the surge suppressor.

Abstract: A device for measuring fuel flow to a power plant such as a turbo fan engine with a very high degree of accuracy, for example, .+-.0.5%. A tubular flow loop having quick disconnect fittings for detachably connecting the loop between the aircraft fuel system outlet and the engine fuel inlet is disclosed. Two specially calibrated mass flow transmitters are arranged in series, each preceded by a straight section of piping having a preferred given length to diameter ratio. Preceding each of the two straight pipe sections is a honeycomb flow straightener and three in-series perforated plates for removing any effects of upstream flow characteristics from the transmitters.

Abstract: A full-wave rectifier is implemented in CMOS integrated circuit chip technology. Two transistors are used in a bridge arrangement with two diodes to implement the rectifier while avoiding parasitic transistor action which previously provided an unwanted current path through the chip substrate to defeat full-wave rectification.