Abstract: A data compression method and apparatus particularly suitable for use in electrical power line fault data recorders. The system performs both gain compression and frequency compression. For gain compression, a predetermined number of samples are analyzed to determine a gain setting common to each sample in the set of samples. A reduced data string consisting of a gain code and data words having fewer bits than the input words are transmitted as a compressed data string. For frequency compression, a sample set representing the input signal is decimated until there remain only a sufficient number of data samples to satisfy the Nyquist criterion for the highest frequency component of interest. The frequency compressed output data string comprises a frequency code representing the highest frequency of interest followed by the set of decimated data samples.

Abstract: The finger ring has a mounting which has a face. There is an opening on the face which extends into a cavity in the mounting. A slot on one side of the cavity provides access to the cavity and permits a setting to be slid into the opening where it is exposed from the face of the ring. Preferrably, there is a slideable door which can be used to close off the slot when a setting is in place.

Abstract: A force or pressure sensor includes a monocrystalline silicon diaphragm coated with silicon dioxide upon which single crystalline silicon resistors are fused in a low profile pattern on the surface. The resistors are almost perfectly electrically isolated from each other and from the underlying silicon substrate. The structure is fabricated by forming resistors in a first wafer and then affixing that surface of the first wafer to the silicon dioxide layer on the second wafer. All of the first wafer except for the resistors has been removed, and metal contact capable of resisting elevated temperatures are formed to provide electrical connections to the resistors.

Abstract: A connection assembly comprises a connector and an electronic circuit fixable on the connector. The connector comprises a support having resilient conductive blades fixed thereto. The blades constitute two "under connectors" adapted respectively to cards in accordance with the ISO standard and in accordance with the AFNOR standard. The blades have support-forming material molded thereover during manufacture of the support.

Abstract: The invention provides a ticket issuing system suitable for issuing tickets with or without a stub for use in payment for parking. The ticket issuing system includes a roll (4) of paper having messages pre-printed thereon, a thermal print head (13), a motor (12) for driving the strip of paper, and means (14, 16) for cutting the paper. A control assembly (34) controls these various means to ensure that a driver is provided with a ticket and a stub or with a ticket on its own depending on whether or not the driver has pressed a button (42).

Abstract: A method of calibrating a process computer, of the kind including an analogue to digital converter for converting analogue input signals representative of measured process parameters into digital signals for processing within the computer, and a digital to analogue converter for converting the processed signals into analogue output signals, comprises applying a known analogue signal to the analogue to digital converter, comparing the resulting digital signal with its expected value, and computing and storing a first calibrating correction value in dependence on the difference. A known digital signal is then applied from within the computer to the digital to analogue converter, whose output is coupled back to the input of the analogue to digital converter for conversion thereby and correction in accordance with the first calibrating correction value.

Abstract: A data compression method and appartus particularly suitable for use in electrical power line fault data recorders. The system performs both gain compression and frequency compression. For gain compression, a predetermined number of samples are analyzed to determine a gain setting common to each sample in the set of samples. A reduced data string consisting of a gain code and data words having fewer bits than the input words are transmitted as a compressed data string. For frequency compression, a sample set representing the input signal is decimated until there remain only a sufficient number of data samples to satisfy the Nyquist criterion for the highest frequency component of interest. Also included is a circuit for reproducing the waveform envelope. Positive and negative peak detectors provide signals representative of the peaks of the waveforms.

Abstract: An improved temperature transducer for use with a KYZ pulse data recorder. A temperature sensor provides a temperature signal proportional to ambient temperature. An integrator circuit and comparator circuit responsive to the temperature signal provides pulses at a frequency which is proportional to temperature. The pulses are provided over the standard three-wire KYZ pulse cable to the input of the data recorder. The circuit is extremely low power, highly accurate, and requires only the three-wire KYZ connection. No external power supply or cable is required, since the circuit draws its power from the pull up resistors in the KYZ data recorder input. Also disclosed are techniques for improving accuracy and minimizing power consumption in the circuit, and an improved integrator circuit.

Abstract: A system for controlled meter parking of road vehicles comprising a parking meter and a portable terminal for use by a checker of the controlled meter parking. A keyboard allows drivers to enter vehicle data. A parking time limit is calculated as the function of the amount of money paid. The parking meter then stores pairs of data items, where each pair contains a vehicle data item and an associated parking time limit. In one embodiment, the amount of money is read from a memory card to allow the driver to receive credit for any time not used upon return to pick up the car. The system includes a clock for comparison with the parking time limits. When the comparison with the clock indicates that a parking time limit has expired, the associated pair of data items are deleted from the parking meter memory. A portable terminal allows a checker to enter identification data corresponding to a vehicle actually parked in one of the parking spaces.

Abstract: A device for reading and/or writing electronic memory cards, said device providing protection against acts of vandalism. The card is guided by slideways. The read/write head is disposed in a zone of a card-receiving housing, which zone is separated from the front zone thereof by a vertical partition provided with a slot for enabling the contact tabs of the card to come opposite the read/write head. At least in said separate zone, the housing is free from abutements or walls that impede card displacement, thereby making it difficult to leave a card or a card fragment jammed inside the device to prevent further use thereof. Advantageously, the card is brought into electrical contact with the read/write head by curving the card, thereby making it difficult to damage the electrical contacts of the read/write head.

Abstract: The present invention relates to a device for starting telephone charging in a pay phone.The starting device essentially comprises a scrambler circuit (42) which is inserted in the line (26) when the handset is taken off-hook and which is inhibited only when the user actuates a pushbutton (20), and a microphone inhibit circuit (40) which is inserted when the user dials the called number and which inhibits simultaneously with the circuit (42). Charging begins when the button (20) is actuated.

Abstract: An electronic token for use with a prepayment commodity meter such as an electricity meter comprises a key-like device 10 having a head 12 containing an electronic circuit and a body portion 14 for insertion into a keyway in a receptable 40 in the meter. The body portion 14 has grooves 24 which serve to guide the body portion into the keyway, and which contain electrical contacts 28, 30 connected within the device 10 to the electronic circuit. Between the body portion 14 and the head 12, the device 10 is provided with a locating recess 27, which engages a projection 78 in the receptacle 40 when the body portion is fully inserted into the keyway. The receptacle 40 incorporates a combined shutter 98 and spring 102, which serve to close the keyway in the absence of the device 10, and to urge the body portion 12 to one side of the keyway during insertion, such that the recess 27 engages the projection 78 and the contacts 28, 30 engage contacts 68, 72 in the receptacle.

Abstract: A device for providing rotary electric coupling for a recorder/reader of magnetic tape including at least one magnetic head (21, 22) which is rotated at the periphery of an equatorial slot in a cylindrical drum over which the helically wound tape is caused to run. Said device is intended to transmit electrical signals representative of information recorded on or read from said tape, between a rotor-forming rotating portion connected to the head and a stator-forming stationary portion connected to electronic means respectively for emitting and/or receiving said information. The device further includes a two-plate capacitor (29, 42) for each of its heads (21, 22), said capacitor plates being disposed facing each other in pairs and one plate in each pair being fixed to the rotor and the other to the stator.

Abstract: An optical transducer system for producing an optical output signal representative of the rotational speed of a rotary member, particularly a shaft of a gas turbine engine, comprises a conventional inductive speed probe positioned adjacent the shaft to sense the passing of the teeth of a toothed wheel secured to and rotatable with the shaft. The inductive sensor thus produces an AC output signal whose frequency is proportional to the rotational speed of the shaft, and this signal is used to excite electrostatically vibration of a cantilever beam micromachined in silicon. The vibrating beam is arranged in an optical path defined by one or more optical fibres, such that its vibrations modulate light directed along the optical path at a frequency which is again proportional to the rotational speed of the shaft.

Abstract: A thermocouple, particularly for use in a gas turbine engine, comprises a mineral-insulated thermocouple element having its sensing end reduced in diameter by swaging, to increase sensitivity and reduce response time. Instead of swaging the whole sensing end to the reduced diameter, with a relatively large taper angle, typically about 14.degree., between the swaged and unswaged portions, the end is provided with a more gradual taper extending over substantially its whole length and having an inclusive taper angle of not more than 5.degree., and preferably about 21/2.degree..

Abstract: The invention relates to a system for mutual authentication between a transmission line and a terminal, e.g. a prepayment telephone set.The telephone (2) is connected to the line (14) via a monitoring device (18). Electronic circuits (18) and (12) are associated with the monitoring device and with the telephone in order to generate authentication frequency signals throughout the call at inaudible frequencies.

Abstract: Apparatus for processing smart cards, each card comprising a body, electrical contact tabs, and an integrated circuit placed in the card body and electrically connected to said tabs, said integrated circuit including storage means for storing monetary amounts unit-by-unit as the card is used, said apparatus comprising:processor means capable of processing data stored in a card and suitable for feeding electrical power to said integrated circuit;electrical connections suitable, when a card is in a determined position suitable for enabling data to be read from and/or written to said storage means, for inter-connecting said processor means and said integrated circuit in a card via said contact tabs; andmarker means under the control of said processor means for marking the body of a card with marks representative of the quantity of charge units in the card which have already been used up.

Abstract: DC magnetic flux bias imposed on a magnetic core of a current transformer is compensated in response to an indication of the amplitude and duration of opposite polarity secondary winding current components. In a second embodiment, the magnetic bias is compensated by responding to the integral of the secondary current. The integral of the secondary current is a measure of the magnetic core flux variations. The durations of the positive and negative flux variations are compared.

Abstract: A shaft monitoring system for sensing axial movement of a shaft, especially in a gas turbine engine, comprises a toothed wheel attached to and rotatable with the shaft, and a pair of inductive sensors disposed radially of the toothed wheel for sensing the passage of the teeth as the shaft rotates. In one embodiment, the toothed wheel has two axially-spaced sets of teeth, one set straight cut and the other set diagonal cut, so that the phase difference between the respective outputs of the sensors varies with axial movement of the shaft. In another embodiment, the sensors are positioned at opposite axial ends of the toothed wheel, so that axial movement of the shaft causes one sensor output to increase in amplitude while the other decreases.

Abstract: A solid sensor, for sensing a physical parameter such as pressure, comprises a resonantly vibratable beam formed across a cavity in a substrate by micro-machining, and arranged such that changes in the parameter vary its resonant frequency. The beam either consists of or has deposited on it a material exhibiting piezo-electric effect, so that vibration of the beam can be excited by using the effect. This is achieved using light, either by forming a photodiode in the substrate in or near the beam, so that illuminating the photodiode causes a voltage to be applied to the beam, or, in the case where the piezo-electric material exhibits surface piezo-electric effect, by directly illuminating the beam.