Abstract: A molded plastic fixture holds an end of a telephone wire cord wound on a mandrel to retain the cord in position during subsequent heat processing. The mandrel fits into a bore in the fixture and an angled arm extending from one side holds a band spacer and strain relief member at the end of the cord. An opposite side of the fixture includes a channel to receive cords with no strain relief member. A manually adjustable screw clamps the end of the mandrel within the bore of the fixture.

Abstract: An underground station is provided with an access cover assembly including a frame extending about an access opening and a cover hingedly attached to said frame. A support member is attached to said frame and extends about the periphery of the access opening. Attaching members are slidably mounted to said support member so that they may be positioned to any desired location about the periphery of the access opening. Fastening means are provided for fixing said attaching members at desired locations about the support member and for fastening station accessories to the attaching member so that the accessories may be mounted in preferred locations in a particular station.

Abstract: The invention provides a circuit for an all-pass reverberator with an MOS delay line and feed back amplifier. The circuit compensates for the frequency-dependent attenuation of the delay line. Two amplifiers of the prior art circuit are replaced by resistors and a third one has specific characteristics.

Abstract: An electrical push-button switch in which the push button has a shank extending through a passage in the switch housing for engaging an electrical contact set. The passage through which the shank extends has a series of notches around the periphery for receiving one end of a pair of springs, the other end of each spring is attached to the shank. The springs have an N-shaped configuration with an extension at one end of the N. A pair of complimentary stationary portions of the switch housing extend in the path of and engage the extended portions of the springs after the push button is depressed. The initial depression of the push button causes the shank to move against the tension of the springs until a changeover point is reached, thereafter the push button movement is assisted by the springs for a further period of travel.

Abstract: A constant output pump delivers a portion of a fluid, the viscosity of which is to be controlled, into a measuring capillary tube to develop a pressure differential across the measuring capillary tube. Means are provided to sense the pressure differential and control the fluid viscosity in response thereto. A second capillary tube is adapted to receive all of the fluid discharged from the measuring capillary tube and an elastic fluid space is interposed between the measuring capillary tube and the second capillary tube. The flow resistance of the second capillary tube and the elasticity of the fluid space functions to make the pressure differential independent of static fluid pressure changes.

Abstract: This relates to a bucket-brigade delay line wherein clock frequency dependent modulation of the delayed signal is avoided by inserting at least one inverter stage into the delay line. The output of the inverter stage contains the inverted modulation signal. This signal is then added to the line thereby compensating for the unwanted modulation.

Abstract: A reverberation device is provided with a delay line in series with an amplifier which is designed to compensate for the inherent frequency dependent attenuation of the delay line. The output of the compensating amplifier is fed back directly to the delay line input.

Abstract: There is disclosed a digital conference bridge for a delta modulated switching system having information transmitted by delta modulation bits in M channels of a time division multiplex frame, where M is an integer greater than three. N conferees, where N is an integer greater than two but less than M, are interconnected by a time switch to enable a conference to take place among the conferees. N three stage shift registers are provided, one for the delta modulation bits of each of the conferees. N sequence detectors are coupled to an associated one of the shift registers to produce a binary 1 output when bits stored in the shift register are all binary 1 or all binary 0. N counters each have their count increased by the binary 1 output of an associated one of the sequence detectors. A count comparator is coupled in common to all the counters and produces a control signal indicating a new speaker for the counter having the largest count.

Abstract: A fault detection process and system is disclosed for large multistage time division-space division-time division switching networks. In the input time-division switch an origin bit is simultaneously transmitted with each sample to the related output channel of the output time division switch. The origin bit is produced by modulating a selected bit of the input channel address by an associated sample parity bit. In the output switch the modulated origin bit is demodulated by the received sample parity bit. This demodulated origin bit is compared with the corresponding bit of the input channel address which has been stored in a memory of the output switch under control of the network computer unit. In addition, means are provided for taking into account input delay, transmission delay and output delay.

Abstract: This relates to an optically isolated switching device made by coupling the output of a light emitting diode into a thyristor. Sensitivity is determined by optical flux density rather than total flux. Improved sensitivity is obtained with a mesa construction of a diode mounted on and bonded to a thyristor at a window in its cathode via a glass preform having a high refractive index.

Abstract: A polarizing D.C. voltage is generated at the capacitance of the ultrasonic transducer and then short-circuited by a parallel-arranged electronic switch controlled by the command signal frequency to be radiated. A direct current stored in an inductance during this short-circuit phase is supplied via a decoupling diode to the electrodes of the ultrasonic transducer upon opening of the switch, and after having been transformed into a voltage. The polarizing D.C. voltage is thus re-generated periodically.

Abstract: A device for scanning optical images wherein light intensity of a scanned image line is converted to a pulse width modulation rather than a charge profile. A photo transistor row is connected to an inverter chain, and OR-gates have outputs which are fed to a common read line while the input signal of each OR-gate is tapped over coordinated partial rows of the photo transistor row.

Abstract: A method and structure are provided for the simplified batch fabrication of Gallium Arsenide-Aluminum Gallium Arsenide lightemitting diodes. A high aluminum content AlGaAs layer is formed on the GaAs substrate layer to provide an etch resistant mask, and an etchant is employed which preferentially etches the GaAs. This permits simultaneous etching of the substrate to form a plurality of like devices on a common semiconductor wafer in a repeatable low-cost batch process.

Abstract: Heater for indirectly heated cathodes with a homogeneous dark colored insulating layer which is formed by introducing aluminum oxide, tungsten oxide and chromium oxide, all in powder form, into a coating bath and coating the heaters in a combined electrophoretic-electrolytic process by dipping them into the bath only once.Advantages: simplified production (only one coating process); improved heat radiation; short heating time; longer service life.

Abstract: A pump is provided with a stationary impeller housing having a motor driven diagonal impeller mounted therein. A diffuser is mounted coaxially with the impeller for converting the kinetic energy of the pumped fluid into a pressure head. A hollow body mounted in the diffuser defines a diffuser passage in which curved diffuser blades are mounted. The impeller has a conical hub having a diameter equal to 40-80 percent of the maximum diameter of the impeller blades.

Abstract: This invention relates to selenium rectifiers and a method of making them. Using techniques of electrophoretic deposition of selenium, a selenium rectifier is manufactured having a barrier layer adjacent the base electrode. This results in a cheaper rectifier with improved heat dissipation.

Abstract: The invention provides a circuit for centrally generating the horizontal and vertical sweep frequencies in a TV receiver. A central oscillator provides a frequency which is divided to obtain the horizontal frequency. A periodic counter with adjustable final counting value divides the central oscillator frequency to establish a vertical sweep signal. Phase comparators and gate circuits are used to gate the oscillator signal to the periodic counter to synchronize the vertical sweep with the transmitted vertical sync signal.

Abstract: A glass-metal powder mixture, preferably including silver, is used in place of the usual epoxy resin-silver outer layer of a tantalum capacitor. This reduces temperature sensitivity during soldering and avoids penetration of silver into the graphite and manganese dioxide layers of the capacitor. Thinner layers of graphite and MnO.sub.2 can be used and reduced carbonization provides improved conductivity. A small solder bead can also be used instead of dipping into a solder bath.

Abstract: Misregistration and losses between the ends of coupled optical fibre-bundles are reduced by tapering the fibre ends. The ends are etched to remove a portion of the outer cladding glass around each glass core. The tapered ends are inserted into a low refractive index glass tube and drawn down in the tube to form a solid core glass zone. The solid end is polished to facilitate coupling to another bundle.

Abstract: This invention relates to a gated frequency difference detector for use in a frequency lock loop. The gated frequency difference detector consists of a dual output hybrid quadrature mixer, two parallel video signal processing channels, a digital phase/frequency detector, a digital scaler and a digital-to-analog converter. The difference in frequency between the RF input and the output of a local oscillator is measured. Two orthogonal frequency difference outputs are first generated, one of which either leads or lags the other depending on the sense of the difference. Signals are then bandwidth limited and amplified in two video channels and converted to logic levels. The phase and frequency are finally digitally detected and processed to generate a bipolar voltage proportional to the magnitude and sense of the frequency difference.