Abstract: In an anti-ESD protective structure, especially designed for pins destined to reach below ground and/or above supply voltages, includes a pair of Zener diodes or lateral NPN structures with a resistive connection between base and emitter, connected in opposition among each other between the pin to be protected and a grounded substrate of the integrated circuit. An amplifying effect on the leakage current which is drawn/injected through the pin by the protective structure caused by the triggering of an intrinsic parasitic transistor is effectively eliminated by connecting a biasing element, such as a forward biased junction, between the node of interconnection between the two Zener orlateral NPN structures and a node of the integrated circuit biased with a voltage sufficiently high as to ensure, under any condition, a reverse biasing of the base-emitter junction of the parasitic transistor.

Abstract: A contactor circuit couples electrical power to a load, and has a current sensor responsive to a level of current for generating an output signal level when the current exceeds a fault threshold. A control circuit coupled to the output signal has a trip output that changes level with the output signal of the current sensor, coupled to its reset input via an indicator circuit, whereby the control circuit is reset when the current exceeds the fault threshold. A bell alarm circuit picks off the trip output for operating an alarm device. The bell alarm circuit has a comparator with an input coupled to a capacitor charged through a resistor and a transistor arranged to discharge the capacitor when the trip output is low. The transistor is responsive to an optical coupler arranged in the indicator circuit in parallel with an indicator LED that is blinked by the control circuit.

Abstract: An apparatus for converting source data into modulation data includes a compressed look-up table based on a conversion correlation, a non-effective data discriminator, a group discriminator, an output flag generator, a flag modulator, a control signal generator and an output compensator. A first address having the source data and a original input flag and a second address having the source data and a modulated input flag are sequentially applied to the look-up table which in turn generates first tentative data and a first tentative flag with respect to the first address, generates second tentative data and a second tentative flag with respect to the second address, and produces unique non-effective data when non-effective data is applied.

Abstract: The protective device applies to an installation comprising a rack in which are engaged modular functional elements interconnected by means of an interconnecting circuit provided at the back of the rack. It uses a connector element mounted on the rack and whose connection pins are electrically connected to conductors of the interconnecting circuit, and a protective module comprising a case accommodating protective circuits linked to connection members of a second connector element susceptible of connecting into the first connector element in order to provide a disconnectable electrical link between the conductors and the corresponding protective circuits. The invention applies notably to the protection of the electronic installations situated on board an aircraft.

Abstract: A self powered trip indicator remotely reads out parameters such as the type of trip detected in a contactor or motor starter circuit controllably coupling a power line to a load. The contactor circuit imposes signalling pulses on a trip status signal following a transition of the signal to a fault-indicating level, the pulses representing the parameters. The remote trip indicator derives operative power from the trip signal, and decodes the parameter from the pulses, using a decoder such as a counter to accumulate a binary multiple count of pulses, the result being indicated on LEDs coupled to outputs of the decoder. A switching circuit generates a short reset pulse to the counter at a leading transition following a pulse or level of a width exceeding a time limited by an RC combination coupled to the counter reset input.

Abstract: A telephone station protector module suitable for exposure to weather includes an elongated lower hollow housing member has a longitudinal and a transverse axis. The top surface includes a pair of terminal assemblies with the front and rear surfaces parallel to the module's longitudinal axis and include an elongated through aperture and an open bottom. Each terminal assembly includes a pair of hollow rectangularly shaped upper housing members having a top surface with an aperture adapted to receive a threaded bolt. Two side surfaces parallel to the transverse axis are provided with a plurality of apertures suitable for receiving insulated wires therein. The other two parallel sides surfaces are provided with an outwardly extending protrusion for cooperating with the bottom member elongated aperture. The terminal assembly also includes a generally U-shaped conducting contact, which has a pair of arm portions and a base portion.

Abstract: A circuit for sensing the loss of a signal ground in an automotive electronic system having a source of electrical power and both a signal ground and a power ground, includes a first sensor coupled to the power ground and between the signal ground and the source of electrical power for generating a first signal responsive to the voltage on the signal ground differing from the voltage on the power ground by more than a first predetermined limit. A latching semiconductor switch is coupled to the first sensor and between the signal ground and the power ground for latching the electrical coupling of the signal ground to the power ground responsive to receiving the first signal.

Abstract: A modulating method, a modulating device and a demodulating device, in which it is possible to improve the digital sum value (DSV) of the coded information, modulated for transmission or recording on the recording medium, are disclosed. An encoding circuit 11 translates a sequence of input data into a sequence of coded data suitable for transmission. A pattern generating circuit 12 generates a pattern of a pre-set length at a pre-set interval inversely proportionate to the low-range cut-off frequency of the modulated coded data. A pattern inserting circuit 13 inserts the patterns into the sequence of coded data A at the pre-set interval. A modulating circuit 14 NRZI modulates the pattern-interlaced sequence of the coded data B and outputs the resulting sequence. A timing control circuit 15 controls the pattern inserting circuit 13 an so forth.

Abstract: A solid state overload relay utilizes an apparatus that converts the current of a polyphase electrical load to a voltage signal approximately proportional to the RMS current of the load. In addition to providing the overload function, the voltage signal is used to provide an improved phase current unbalance protection. Conventional current transformers sense the current flow in each phase of the load. The current waveform for each phase is converted to a voltage by rectification and the peak value and the average value of the resultant voltage is determined. A summing circuit combines the two values at a predetermined ratio to create a DC voltage that is approximately equal to the rms value of the input phase current. A combination of the approximation circuit with a time integrating circuit and a level detecting circuit produces a low cost solid state overload relay in one embodiment of the invention.

Abstract: A cross connect system for telecommunication wires reduces the required time to install and effect cross connections if the wire connections are made by hand and changes are made between circuits by unplugging a modular plug and plugging it in at a different position. The connector of the present invention has a terminal block accepting a plurality of plugs connected each to a pair of wires and the plugs fit onto the terminal block or can be stacked on each other for half tapping, testing or transferring. Protected plugs may be provided having overvoltage protection circuits, and jumper plugs may be stacked onto such protected plugs.

Abstract: A secondary surge arrester has a line conductor and a ground conductor extending through a casing. A nonlinear voltage dependent resistive element and a fault current limiting fuse are connected between the conductors and are disposed within the casing. The fault current limiting fuse includes a fusible material surrounded by sand. The sand also surrounds the nonlinear voltage dependent resistive element. A heat sensitive material is disposed in close proximity to the fusible material and is viewable through a transparent cover. In the event of a failure of the nonlinear voltage dependent resistive element causing arcing, the fusible material fuses to open the current path between the conductors, and the sand absorbs energy by transforming state. Thus, the fault current limiting fuse limits current flow through the surge arrester and extinguishes the arc within the surge arrester so as to prevent violent fragmentation of the casing.

Abstract: A switching circuit has a pull-up FET and a pull-down FET coupled to a load circuit, each FET having a control terminal coupled to a current regulating circuit. The current regulating circuit provides a high predetermined current for a relatively short duration to the gates of the FETs to quickly turn on or turn off the FETs. After the short duration, a low quiescent current is applied to the gates to maintain the FETs in their present states. An inhibiting circuit, coupled between the pull-up FET and the pull-down FET, detects the states of the FETs and delays turn-on of one FET until the other FET has turned off. An overcurrent circuit monitors a current through a switching FET and turns off the FET after a predetermined time delay when an overcurrent condition is detected. The overcurrent circuit then turns on the FET after another predetermined time delay.

Abstract: A circuit and method for controlling the application of a fastener to a surface and a support, for use with a support sensor and an automatic fastener applying device. In the circuit, a comparator receives a primary signal from the sensor and generates an intermediate signal when a preselected condition is satisfied between the primary signal and the predetermined value. A controller generates a control signal in response to receipt of a secondary signal from the sensor and the intermediate signal. An actuator operates the automatic fastener applying device to apply the fastener to the surface and support in response to the control signal.

Abstract: An architecture for oversampled delta-sigma (.DELTA.--.SIGMA.) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage .DELTA.--.SIGMA. modulators that incorporate band-reject noise shaping centered at an arbitrary center frequency F.sub.bp. These modulators cascaded with a bandpass digital filter centered at the arbitrary center frequency F.sub.bp perform A/D conversion for high-frequency, narrow-band signals having the same arbitrary frequency. The bandpass modulators are implemented by use of resonators which provide a substantially large gain at the arbitrary frequency.

Abstract: Independently of a punch-through MOS transistor Q.sub.3 used as an I/O protection element in which the drain is connected to an input node or output node and the source is connected to a GND or Vcc, an element for-setting the gate of punch-through MOS transistor Q.sub.3 to the GND potential is provided so that its operating speed may be slower than the punch-through speed of the punch-through MOS transistor Q.sub.3. In consequence, a high surge applied from I/O terminal can be punched through before the gate insulating film of the punch-through transistor Q.sub.3 undergoes a high electric field, to thereby protect the gate insulating film.

Abstract: A circuit analyzing system includes a current transformer for extracting current from a phase or neutral conductor of a three phase line, a filter connected to the output of the current transformer and functioning to substantially trap current at the fundamental frequency while substantially passing currents at various harmonic frequencies thereof, and signal processing circuitry connected to the output of the filter to perform various functions with the harmonic frequency current input thereto. Among these functions, as shown in various preferred embodiments, are measurement of the harmonic signal in RMS and conveyance of the output to a display instrument for a user or utility's convenience in monitoring harmonic frequency circuits, which have become more common with the advent of electronic equipment having internal power supplies such as personal computers, work stations, printers, and the like.

Abstract: A method and apparatus for digital-to-digital conversion using sigma-delta modulation of the temporal spacing between digital samples. The method and apparatus of the present invention provides for sigma-delta modulation of the time base such that noise produced by non-uniform sampling are frequency-shaped to a region (i.e., shifted to higher frequencies) where it can be removed by conventional filtering techniques. In one embodiment, the digital data is interpolated by fixed ratio and then decimated under control of a sigma-delta modulated frequency selection signal that represents, on average, the data rate of the incoming digital data stream. Thereafter, the digital data is interpolated under control of a sigma-delta modulated frequency selection signal that represents, on average, the data rate of the digital data to be output by the converter and then decimated by a fixed ratio. The first and second frequency signal selection numbers are modulated using n-th order m-bit sigma-delta modulators.

Abstract: An overload protective apparatus has fixed contacts connected to at least one pair of fixed terminals secured on the bottom of a case, a dish-shaped polymetallic element, e.g., a bimetal or trimetal having movable contacts bonded thereon so as to oppose the fixed contacts, and an adjusting bolt supporting a central portion of the polymetallic element for maintaining the polymetallic element at a position separate from the bottom of the case, wherein the polymetallic element and the adjusting bolt are accommodated in the case. The polymetallic element used herein is constructed to make a current density around bonding portions for the movable contacts higher than other regions, such that portions around the movable contacts are more susceptible to rupture when an abnormal current flows through the polymetallic element. The polymetallic element is also constructed to prevent degradation of the spring constant thereof.

Abstract: A system of protection for an electric power generating system having a poly-phase generator switchably coupled through a generator control breaker to a load distribution bus, wherein the generator output voltage is controlled by a generator control unit which utilizes isolated voltage and current sense signals having a magnitude proportional to the output voltage and current for each phase of the poly-phase generator, the isolated voltage and current sense signals being generated by isolated voltage and current sensors, comprises a first circuit for monitoring the magnitude of each of the isolated voltage sense signals and generating a first output control signal if the magnitude of any isolated voltage sense signal is below a first predetermined threshold.

Abstract: In a multiple contactor installation where each contactor provides overcurrent protection, overload information in passed from one active contactor to the next as a percentage of the trip level of the respective contactors.