Abstract: A multiplexer having a plurality of semiconductor solid state input switches arranged to be connected to respective input signal sources and arranged in groups of input switches with a plurality of the switches in each group, a plurality of selectable leakage current shunting circuits with each circuit being connected by a leakage current control switch to a respective one of the groups of the switches to provide a shunt path for leakage currents through the switches in a corresponding group and a switch control for selectively operating the solid-state switches to connect a selected one of the input signal sources in a selected one of the groups of sources to an output of the multiplexer and the leakage current switches in the non-selected groups to connect each of the solid-state input switches in the non-selected groups to the respective ones of the current shunting circuits.

Abstract: A circuit arrangement for adjusting the operating voltage of high-pressure gas discharge lamps to a given nominal value, comprises a controllable current limiter connected in series with the lamp and an adjustment circuit (3) for controlling the latter. The output signal of the adjustment circuit is determined by the difference between a given desired value determining the nominal lamp operating voltage and an actual value dependent upon the instantaneous lamp operating voltage. In parallel with the lamp (1) a heating element (5) is arranged which is in thermal contact with a temperature-dependent electrical element (6), which produces the actual voltage dependent upon the instantaneous lamp operating voltage.

Abstract: A high-power switch network includes a laser fiber optically coupled to a network including light-initiated glow discharge switches in a Marx configuration. A low pressure gas source is used to replenish gas within the switches lost due to ionization. Each switch has a cylindrical insulating envelope with conductive end caps at each end. The end caps are electrically coupled, respectively, to a cup-shaped anode and a cup-shaped cathode. Apertures are formed centrally in closely spaced plates of the respective cup-shaped electrodes. Optical fiber cables extend through vacuum sealed ports of the switches so that the unfocused laser light is directed about the aperture of the cathode so as to close the switch, thus providing a high power output from the network.

Abstract: An apparatus for judging the quality of mobile data communication has: (1) a unit for amplifying an incoming electric wave and detecting the strength of the received electric field; (2) a data communication judgement unit for previously setting a limit of data communication, and comparing the reference value with an output from the electric field strength detector unit (3) a visible display unit for visually displaying the received electronicfield signal when the strength of the received electric field is more than the judgment reference value; (4) a digital output terminal for outputting a digital control signal to control a modem; and (5) an audible tone generator for producing a continuous tone or an intermittent tone from a speaker to clearly inform an operator of the quality of the data communication when the strength of the received electric field is less than the judgment reference value.

Abstract: A radio transmitter includes a bank of pre-distortion circuits each of which is selectively connectable between the mixing stages of the transmitter and the final linear power amplifier stage of the transmitter. The pre-distortion circuit to be connected is determined by the RF frequency of the signal to be transmitted. A method of analyzing the distortion produced by a linear power amplifier is also described. In this method two tones are applied to the amplifier and the resulting down-mixed signal is subjected to a FET in order to derive the spectrum and plot the amplitude and phase distortion against the two tone amplitude. Analysis of the results of such testing allows the pre-distortion circuits to be designed to compensate for distortion produced by the amplifier over the complete operating frequency range of the transmitter.

Abstract: It is an object of the invention to provide a miniature traveling wave tube which will have most of the advantages of solid state circuitry but with higher efficiency and without being highly sensitive to temperature and various types of electromagnetic radiation and subatomic particles as are solid state devices.The traveling wave tube which is about 2.5 cm in length includes a slow wave circuit (SWS) comprising apertured fins with a top cover which is insulated from the fins by strips or rungs of electrically insulating, dielectric material.Another object of the invention is to construct a SWS of extremely small size by employing various grooving or etching methods and by providing insulating strips or rungs by various deposition and masking techniques.

Abstract: A thyratron includes a grid structure in which a grid element has a plurality of apertures therethrough, each of the apertures comprising two arcuate portions at different distances from the center of the grid which are connected by a radial portion. Thus a large grid area may be provided without detrimentally affecting voltage hold-off, jitter or mechanical soundness.

Abstract: An apparatus and a method for fast acquisition of the sample-timing phase in systems using partial-response signalling are disclosed. For fast initial adjustment of the timing phase, a known preamble is transmitted. During that phase, previous schemes could occasionally hang up for an extended period of time at the unstable equilibrium point halfway between the desired sampling times. The new procedure eliminates the hangup problem by introducing a hysteresis effect which greatly diminishes the probability of reversals in the once chosen direction of timing-phase adjustment. Thus, reliable adjustment of the timing phase with a much shorter preamble is achieved. The apparatus for furnishing a timing correction signal .DELTA..tau..sub.n includes a timing gradient generator portion (41) and a data sample reconstruction portion (43). The data sample reconstruction portion (43) develops a present reconstructed data sample x.sub.n from the present received signal sample y.sub.

Abstract: A system for adjusting the synchronizing signal received by an ENDEC receiver in a token ring network is disclosed. The system used lookahead logic in conjunction with the packet delimiter byte to adjust the synchronizing signal without delaying any bits received by the ENDEC receiver. This system has significant utility in Fiber Distributed Data Interface (FDDI) networks.

Abstract: High transmission and reception quality is achieved in a high definition television system, with minimum intra-channel interference, by digitally encoding the enhancement information and employing spread-spectrum modulation techniques.

Abstract: The present invention relates to a driving circuit of a thin film electroluminescent (EL) display, wherein a high withstand-voltage driver IC composed of a bi-directional switching element having push/pull function is connected with one or both of the scanning electrodes and the data electrodes of EL display, the bi-directional switching circuit for applying the writing voltage or the modulation voltage is applied with the pull up common line of each of the drivers IC and the pull down common line, a switch for extremely recovering, after the thin film EL element has emitted its light, the electric charge accumulated on the thin film EL display element, and a capacitor for accumulating the drawn out electric charge are disposed in the bi-directional switching circuit, and the modulation accumulation electric charge accumulated on the film EL display element after the light emission is accumulated on the capacitor, so that the modulation consumption power occupying the majority of the driving power without the

Abstract: A polarization diversity light receiving system using base combining is disclosed, which is arranged so that the control signal for the local oscillator laser is the sum of squared values of received signals.

Abstract: The present invention provides a timing recovery technique for baseband-coded data sequences which applies to line codes with inband timing information embedded in periodic signal transitions, such as zero-crossings. The technique utilizes a selection of data patterns, like mark-to-mark, which have zero-crossings at the "center" of a transition from a positive to negative mark. These so-called "bipolar patterns" consist of two polar-signals of opposite polarity sharing neighborly baud intervals. Because the random nature of a data sequence gives timing information a statistical behavior, a timing recovery system recovers a timing average, the efficiency of the system being given in terms of the timing variance. According to the present invention, a low variance estimate for the bipolar-pattern-center timing signal is obtained by proper filtering.

Abstract: In a magnetron, two rods are supported by a stem in cantilever fashion and a filament (cathode) is connected between two end hats attached to two free ends of the rods. Therefore, these two rods are apt to be vibrated by an external force (e.g. an air screwdriver) during assembly or in transit. To suppress relative displacement of the two rods of magnetron due to external force, the natural frequency of the first vibration system composed of a first rod and a first end hat is determined substantially equal to that of the second vibration system composed of a second rod and a second end hat.

Abstract: An operating system for a sun tanning apparatus comprises an array of multiple parallel-oriented fluorescent lamps and an electronic frequency converter adapted to convert ordinary 60 Hz power line voltage into a 350 Volt/30 kHz sinusoidal voltage provided between a pair of bus conductors and suitable for directly powering each fluorescent lamp by way of a simple capacitive or inductive current-limiting reactance means. The fluorescent lamp cathodes are heated by way of individual transformers, with one transformer for each pair of lamp cathodes. Only two pairs of conductors are required for powering the complete array of mutually parallel-disposed fluorescent lamp pairs regardless of the number of lamps involved, with one pair running along the one side of the array, and the other pair running along the other side of the array. Of each pair of fluorescent lamps, one lamp is powered by way of an inductive reactance means and one lamp is powered by way of a capacitive reactance means.

Abstract: A sun tanning apparatus has an electronic operating system comprising: (i) a plurality of pairs of fluorescent lamps for providing tanning radiation, each pair of lamps being adapted to be powered from 30 kHz/120 Volt by way of a high-Q series-resonant L-C ballasting circuit; (ii) a relatively low-power frequency converter connected with the power line and operable to provide power for heating the cathodes in these fluorescent lamps, thereby conditioning the lamps for easy starting; (iii) a relatively high-power frequency converter also connected with a power line and operable to provide the 30 kHz/120 Volt required for operating the plurality of pairs of fluorescent lamps by way of the high-Q series-resonant L-C ballasting circuit; and (iv) delay means operable to prevent the 30 kHz/120 Volt provided by the high-power frequency converter from being applied to the fluorescent lamps until after power has been applied to heat the lamp cathodes for at least one second.

Abstract: The electric lamp has a lamp vessel (1) having an end portion (3) which is fixed inthe lamp cap (5) by means of polyethersulphone (8) as a thermoplastic synthetic resin, which has adhered both to the lamp vessel and to the lamp cap. The end portion (3) has non-circular cross-sections where it is in contact with the synthetic resin (8) due to projections (10) projecting into the synthetic resin (8). A current supply wire (11) can be clamped between the synthetic resin (8) and the sheath portion (6) of the lamp cap (5) in order to establish electrical contact therewith. The lamp can be assembled by arranging in the hot state of the end portion (3) a polyethersulphone ring (8) around this end portion (3) and by providing the lamp cap (5) in the hot state around the polyethersulphone ring (8). FIG. 1.

Abstract: A multi-level quadrature amplitude modulation and demodulation system includes a first exchange circuit for cyclicly exchanging input digital signals and for outputting exchanged signals to D/A converters. The D/A converters provide analog signals to a QAM modulator which produces a modulated signal. In the receiver side of the system, a QAM demodulator demodulates the modulated signal to produce analog signals which are converted to digital exchanged signals by A/D converters. The digital exchanged signals are exchanged in a manner which is the reverse of that of the first exchange circuit to provide output digital signals on output terminals which respectively correspond to the input terminals. By cyclicly exchanging the input signals in this manner, the transmission quality for each of the input signal channels is maintained equal.

Abstract: A high leakage reactance transformer especially for current limited control of gas discharge lamps and other electrical discharge loads has a core with three legs defining two magnetic loops. A first leg has an air gap with a fixed reluctance, a second leg is common to both loops and has a primary winding, and the third leg has a supply winding for connection to the discharge device as well as a control winding connected to a control circuit. The control winding has an adjustable load to vary the reluctance of the third leg and control the current limit of the supply winding. Linear and proportional control circuits are shown.

Abstract: An audio equalization circuit for use in an AM transmission system is described which is particularly useful for compensating for the high frequency rolloff found in currently manufactured AM receivers. A single potentiometer adjustment in the feedback path of the equalization circuit allows the response in the AM receiver to be effectively and economically adjusted.