Abstract: The microprocessor interface device is for use in a telecomminications system including a microprocessor. The device includes a first interfacing means which receives signals from, and dispatches signals to, the telecommunications system. A second interfacing means receives signals from, and despatches signals to, the microprocessor. A memory is provided, together with arbitration means arranged to control the first and second interfacing means so that only one interfacing means at a time has access to the memory. Decoding means is adapted to respond to address signals presented to the second interfacing means by the microprocessor, to generate signals enabling areas of the telecommunications system to be accessed.

Abstract: An electrician's wire bending implement particularly adapted for use with a set of mandrels that are each provided with a drive socket, comprising in combination, an elongate basic wire bending tool, and a graduated array of mandrels that are each equipped with a pair of spaced apart pins. A square drive is provided at one end of the basic tool, and a handle is provided for use on the end of the basic tool remote from the square drive. The handle is to be used on the basic tool when ample torque is to be applied while making lateral bends in heavy gauge wire, using the spaced pins of a selected mandrel that has been mounted on the square drive. Preferably I use a fixed wire forming jaw on the end opposite the square drive, to facilitate creation of fore and aft bends in heavy gauge wire.

Abstract: The invention concerns call-charge payment of telephone calls from payphone telephone instruments (PI) using a credit card, or the like. The invention provides credit transaction arrangements for automatic call-charge payment of calls established through a telecommunications network from payphone instruments (PI). The payphone (PI) is provided with a credit card reader (CRM) which when activated causes the payphone (PI) to automatically set-up a path (NAP) through the telecommunications network to credit transaction equipment (CCE) at a remote location (NP) within the network. Initially, a first record data (HEAD), being relevant to prior call-charge payment, is transmitted over the path (NAP), validated and stored (CDS) at the credit transaction equipment (CCE), and the path is promptly disconnected. The subscriber then sets-up a communication path through the network to a desired called subscriber for communication purposes.

Abstract: A wavelength discriminator designed to collect broadband, multiple wavelength input energy, to isolate specific narrow bands of interest, and to image such narrow bands of interest upon closely spaced, separate detectors. This discriminator comprises optical devices (22, 18) for directing incoming radiant energy of a certain quality and involving a wide range of wavelengths through first (26a) and second (26b) wavelength selective reflectors separated by a medium that transmits the wavelengths of interest. The wavelength selective reflectors in accordance with this invention are in a non-parallel configuration and disposed in a double pass geometrical arrangement wherein energy of a certain wavelength reflected from the second wavelength selective reflector (26b) passes back through the first wavelength selective reflector (26a), with the energy from the first and second wavelength reflectors thereafter being directed onto respective detectors (32aand 32b).

Abstract: Apparatus for obtaining programmable threshold extension of an FM demodulator comprises a limiter preamplifier 4 and a variable gain buffer amplifier 6. The buffer amplifier 6 is provided with an external control node 16 such that the signal level fed from the buffer amplifier 6 to an injection locked oscillator/divider 8 can be programmed in dependence upon a control signal applied to the external control node 16. In this manner threshold extension of the FM demodulator can be selectively applied in dependence upon the noise level in an FM input signal to be demodulated. The limiter preamplifier 4 and the buffer amplifier 6 may form part of an automatic gain control circuit.

Abstract: A circuit arrangement for use in an integrated circuit having a built-in self test design, the circuit arrangement comprising first and second gates coupled to a flip-flop via a third gate. The present invention provides a multiplexer coupled to one input of the first gate, the multiplexer being controllable by a control signal to feed either input data or output data of the circuit arrangement to said one input of the first gate and a fourth gate coupled to an input of the second gate, the fourth gate having an input connected to receive a signal dependent on the control signal to the data selector means.

Abstract: A propellant configuration for a solid propellant rocket motor, comprising a generally cylindrical housing containing a generally cylindrical main grain having a central cavity, and an igniter assembly supported in the central cavity and having means therein for bringing about combustion. At the time of actuation of the igniter assembly, hot gases are directed along flutes formed in the interior of the main grain, to cause burning thereof to take place. Advantageously, the propellant utilized in the main grain is the same as utilized in the igniter assembly, with the burn surface area of the igniter grain being in a pre-established relationship to the burn surface area of the fluted main propellant grain, such that the igniter grain will be totally consumed at the time that the flutes of the main propellant are consumed.

Abstract: The subscriber line signalling device (D) is employed in a digital telecommunications system. In particular the device (D) is used in a subscriber line interface module and it allows all signalling data to be detected and generated on a per-channel basis. A microprocessor (A) controls the device which generates and detects cyclically permutable code words on a plurality of traffic channel paths to or from the device. It is arranged that each generated cyclically permutable code word on any one traffic channel path is synchronously coded with respect to any other traffic channel path. The device can also be programmed to handle different data rates. In addition the operational modes of the traffic channels can be controlled giving loopback facilities allowing cyclically permutable code words to be generated and detected from the input and output traffic channels as desired and allow a diagnostic facility to be implemented.

Abstract: A prior art method of depositing Germanium Carbide involves the use of glow discharge techniques which are problematic in that they require high substrate temperatures. Methods embodying the present invention comprise exposing a target of germanium to a plasma comprising an inert gas and a halocarbon gas. The plasma is maintained by means of a radio frequency magnetron electrode which is associated with the target. Atoms and ions of Germanium and Carbon are sputtered onto the substrate in order to deposit the Germanium Carbide.

Abstract: A high resolution analog to digital converter comprising a low resolution analog to digital converter and an interpolating digital to analog converter, the interpolating digital to analog converter having a second order digital controller and a one bit quantiser arranged in a feedback loop. The low resolution analog to digital converter is coupled to a multi-stage decimation filter having an algorithm of any stage thereof determined in dependence upon the algorithm of the immediately preceding stage.

Abstract: A method of selectively displaying data, whereby the data is arranged in a consecutive series of data-blocks, each data-block being a matrix of information such as a Lofargram. The method comprises selecting an initial set of data-blocks from the series of data-blocks, wherein the initial set of data-blocks comprises an initial data-block and every following nth data-block in the series and then displaying this initial set. The method includes displaying different sets of data-blocks subsequent to the initial set. Each different set of data-blocks comprises an initial data-block, differing from the initial data-block of the preceeding set by an integer m, and every subsequent nth data-block in the series. The method further comprises, displaying a reference data-block adjacent to any one of the sets of data-blocks for comparing with any one of the data-blocks in the series.

Abstract: A power control system for the remote control of one or more remote power supply circuits in which a power controller which comprises means for producing an a.c. control signal which is arranged to be transmitted over a single pair of control conductors forming a part of a d.c. isolated control link to remote power supply circuit for the operation thereof, in which variable impedance switching means at the remote power supply circuit modifies the impedance reflected back over the control link to the power controller in accordance with the condition of the power supply switching circuit and in which detector means in the power controller senses changes in the impedance of the variable impedance switching circuit and accordingly provides an indication of the state of the remote power supply circuit.

Abstract: A method of fabricating optical sensing devices for detecting displacement of a part thereof comprising the steps of bonding a multiplicity of optical devices to one surface of a relatively large transparent substrate so that the optical devices are accurately located relative to one another and to the substrate itself, securing to the opposite surface of the substrate and one surface of a transparent optical element-carrying substrate in parallel relationship thereto resilient spacer support means and dividing the entire assembly into individual unit parts each of which comprises an optical device bonded to one substrate unit and coupled to another substrate unit having its own optical element by a divided part of the resilient spacer support means so that the two substrate units are resiliently mounted relative to one another whereby relative movement between the two substrate units produces variations in the optical characteristics of the device which can be sensed.

Abstract: A target tracking transmitter has an internal voltage supply which may be operated at a first operative level and a second reduced operative level. A switch is provided for cycling the voltage supply between the first and second operative levels, which are both sufficient to ensure generation by the transmitter of radio frequency signals for detection by a remote receiver. The switch is arranged to control the time for which the transmitter is cycled at the first and second levels whereby the operating life of the internal voltage supply is maximized while enabling continuous generation of the radio frequency signals.

Abstract: To facilitate ring trip detection in a telecommunications exchange the ringing signal applied to a customer line is limited to provide a square wave output. Since when the customers instrument is "on hook" virtually no direct current flows in the line, the square wave output has substantial 50--50 duty cycle and when the customer instrument goes "off hook" the d.c. alters that duty cycle, by sampling the square wave signal and counting up for, say, positive samples and down for, say negative samples, any significant change in the duty cycle causes a counter to exceed a ring-trip threshold fairly rapidly. An algorithm and circuit using the algorithm to facilitate identification of "ring trip" based on the above feature are disclosed herein.

Abstract: Featurephone III Provides a line powered loud speaking telephone which meets BSI standards for current drain.To maintain the instrument at a fixed position on a V/I curve a constant current drain is provided across the line form which the instrument amplifier is fed. Accordingly, regardless of amplifier power requirement variations, current drain from the line is constant.

Abstract: The inter-bus system provides the communication interconnection between communication systems to form a large telegraph packet switching exchange for example. The fast inter-bus system uses an RS-485 interface, however, the specific protocol used has particular speed advantages. The inter-bus system consists of a bus converter for each communication system interconnected by a bus involving 16 data bits, a pair of parity bits, clock, abort, transmit active, address strobe and grant return paths. The bus converters are chained by a grant link arrangement. The grant link is used to carry a grant pulse which is passed on around the chained bus converters to identify the master converter for an inter-bus system transfer. When the grant pulse is received by a bus converter wanting to transmit, that bus converter breaks the chain and performs the transmission required. When the transmission is complete the completing bus converter surrenders its master state by generating the grant pulse.

Abstract: An integrated circuit having a built-in self test design, the integrated circuit including a combinatorial logic circuit, a first register coupled to an output of the combinatorial logic circuit and a feedback path via which output signals from the first register are fed back to an input of the combinatorial logic circuit. A multiplexer is provided between the first register and the feedback path, and there is also provided a second register responsive to a signal which is originated to initiate a test function for feeding test signals via the multiplexer and the feedback path to the input of the combinatorial logic circuit.

Abstract: A method of securing a window of crumbly material in the end of a tube so as to effectively prevent leakage during temperature cycling, first involving the step of selecting a window having a small clearance when placed inside the end of the tube. Any contamination is removed from the periphery of the window, and then a thin metallic layer that will accept nickel plate is vapor deposited around the periphery of the window. Subsequently, a hoop of tensilely stressed nickel plate is applied over the thin metallic layer, after which the window and tube are sweated together by the application of suitable amounts of solder and heat. Significantly, the hoop of nickel serves to keep the window in continuous compression, such that leakage between the window and tube is effectively prevented.

Abstract: A fibre optic modulator comprises an optical fibre 2 and a waveguide 10 of active material. The waveguide 10 is dimensioned such that any mode of the waveguide has a propogation constant which is separated from the propogation constant of the optical fibre mode by an amount equal to or greater than .lambda./L where .lambda. is the wavelength of transmitted electromagnetic radiation in the mode of the optical fibre and L is the length of the effective portion of the waveguide of active material.