Showing papers by "NEC published in 1971"

Light-Focusing Glass Fibers and Rods

Abstract: Glass fibers and rods with radially parabolic refractive-index distributions were produced by exchanging potassium ions from a salt bath or a lower-index cladding glass for thallium ions in the glass composition. A fiber 1 m long and 0.25 mm in diameter could be bent around a curve of radius 10 cm without deforming the Gaussian mode pattern; the depolarization of a laser beam was < −20 dB. The resolution of a rod 3.14 mm long and 1.0 mm in diameter with a focal length of 1.64 mm was of the order of 450 lines/mm. Attenuation (caused primarily by absorption induced by trace impurities) was 100 to 250 dB/km at 6328 A; since further improvement with respect to loss is expected, these fiber guides are promising materials for use in long-distance optical communications.

Solid state luminescent display device

Abstract: A solid state luminescent display device comprising a GaAs substrate, a plurality of p-n junctions formed on one surface of the substrate in a predetermined pattern, an infrared-to-visible light converting fluorescent substance mounted on a luminescent region provided at each p-n junction, a plurality of recesses formed on the other surface of the substrate and arranged to correspondingly be aligned with respect to p-n junctions and infrared-to-visible light converting fluorescent substance provided in each recess to enable the device to simultaneously and selectively generate visible light at selective surfaces of the substrate, in accordance with those p-n junctions which are activated.

Multilevel code signal transmission system

Abstract: A binary code is converted into a multilevel code having an average value of zero over a period of time. A group of n multilevel digits is generated representing the same information conveyed by m x n binary bits. Each digit is a (2m+ k)-level digit. One of said n digits represents the information content of m-1 binary bits as well as polarity inversion and synchronization information. The remaining n-1 multilevel digits represent the information content of the remaining m(n-1)+1 binary bits. The integral of the transmitted n-digit codes is converged to zero level. The transmitted n-digit codes are integrated by continually adding the sum of the levels of the transmitted code to the stored sum to generate a new sum or integral. The sign of the integral is compared with the sign of the sum of levels of the currently generated n-digit code. If the signs are the same, each digit of the n-digit code is polarity inverted. The first of the n digits uses only levels of one polarity when the m-1 binary bits are converted into a single multilevel digit. Consequently, whether or not any given n-digit code has been polarity inverted can be detected by detecting the polarity of the first digit. Thus, the first digit carries the total information of m bits by using one of 2m levels excluding k preselected levels. The remaining (n-1) digits are not inhibited to use those preselected levels. However, the first digit is not at those preselected levels. This feature is used at a receiver to obtain word or block synchronization. At the receiver, a sync pulse is generated for every n digit received. If the receiver is synchronized properly, the sync pulse will be in time coincidence with the first digit of each n-digit code. The presence of one of those preselected levels in coincidence with any sync pulse indicates an out of phase condition and the sync pulse is shifted by one digit time.

Switching device for delivering sheet-like articles

Abstract: A switching device for interswitching the delivery of sheet-like articles conveyed to a bifurcation through a feed route, between the main and the branch routes, each route being formed of the opposing surfaces of a pair of endless belts, comprising, instead of the conventional wedge-shaped switching member disposed within the bifurcation, a switching member located outside the bifurcation. The device may be provided with means for rearranging the dislocated sheet-like matters, if any.

Digital transmission channel monitoring system

Abstract: A digital transmission channel monitoring system including means for inserting at a transmitter the equivalent of a binary signal parity check bit into each of the n-digit code words of a multi-level signal. The parity check signal is inserted directly into the multi-level code words by detecting if the algebraic sum of the levels of the digits of each code word is an even or odd number. The level of one of the digits is then selectively changed so that the algebraic sum of the levels of the digits in each word is always either an even number or an odd number. At a receiver, each code word is investigated to determine the algebraic sum of the levels of its digits and an error signal is generated when incorrect parity is detected.

Electronic computer comprising a plurality of general purpose registers and having a dynamic relocation capability

Abstract: A computer memory is divided into segments with reference to the programs being executed. Each pointer to a physical storage address consists of a segment number and a displacement. A program segment base table is provided in the memory for giving the physical base address for each segment. A tag field of at least one bit is provided in each of the general purpose registers and the addresses in the memory, which carries a tag for indicating whether the data word contains address data or the other data. Back-up registers are provided in one-to-one correspondence to the general purpose registers capable of being loaded with the data words containing the physical addresses. On loading a general purpose register with a data word comprising an address as signalled by the tag, reference is had to the segment base table to load the corresponding back-up register with the pointer. On storing in a segment a data word comprising an address as similarly determined, reference is had to the segment base table to store the data word containing the pointer.

Electrooptical device for discriminating a predetermined pattern from others by detecting preselected color changes identifying the pattern

Abstract: A pattern to be discriminated from other patterns comprises a frame of a predetermined size and color on a predetermined background color. The device comprises a first unit for producing electric signals responsive to the color change from the background color to the pattern color and the reversed color change and a second unit, responsive to these electric siganls, for measuring the distance between the boundaries across which the color change takes place.

Open type stacking device

Abstract: A stacking device, which automatically stacks letters, postcards or the like sequentially transported thereto, includes first and second channels for accomodating the letters and conveyor means interposed between said first and second channels for conveying stacked letters from said first channel to said second channel. The respective first and second channels are formed into a Vshape and the conveyor means are arranged in two adjacent planes which are formed into a corresponding V-shape, whereby the adjacent two sides of each of the stacked letters are supported within said channels and on said channels and on said adjacent two planes such that each letter is positioned to be in and maintain its correct orientation. The stacking operation of the sequentially transported letters is executed at the first channel and a removal operation of stacked letters may be performed at the second channel such that both operations may be performed independently of each other.

Improved cathode ray tube having a glass envelope coated with crystallized glass

Abstract: A cathode ray tube including an electron gun enclosed by a glass envelope including a neck portion is disclosed in accordance with the teachings of the present invention wherein arcing between electrodes of the cathode ray tube is minimized by providing a coating of crystallized glass formed by heat-treatment of sealing glass, on the surface of the inner wall of said neck portion and coextensive with said electron gun, and a coating of conductive material, spaced from said coating of crystallized glass, on the surface of the inner wall of said neck portion. A method of treating a cathode ray tube to minimize arcing between the electrodes thereof is also disclosed.

Broadening of Landau Levels in Two-Dimensional Electron Gas. II. Transverse Magnetoconductance

Abstract: Transverse magnetoconductance of two-dimensional electron gas in strong magnetic field is calculated on the basis of the model and approximation used in a previous paper. Calculating two particle Green's function consistently with the approximation for one particle Green's function yields transverse magnetoconductance free from divergence. Strong energy dependence of one particle spectral density leads to some characteristic features of two-dimensional electron gas in strong magnetic fields. Transverse magnetoconductance calculated as a function of gate voltage exhibits broadening of Landau levels and is sharply cut off in midgap regions between Landau levels. These results are discussed in connection with the experiment of Fowler, Fang, Howard and Stiles. Within the model and approximation of the present paper, splittings of Landau levels are also obtained in strong magnetic field.

A frequency division multiplex microwave communication system using polarization division multiplex technique

Abstract: A signal transmission and reception system which includes means for transmitting a plurality of information signals each of which occupies a different frequency band. The information signals, which may correspond to television signals, amplitude-modulate a carrier wave to produce single side band components of the modulated carrier wave, each single side band component corresponding to a different information signal. The components are combined into two groups of side band components each group being comprised of side band components corresponding to alternate, adjacent information signal frequency bands. The two composite signals are transmitted by transmitter means which uniquely polarize each composite signal with respect to the other. Receiving means, responsive to each of the polarized signals, detect the composite signals and apply each to a different demodulator. The demodulated signals are combined to reconstruct the information contained in the plurality of transmitted information signals.

Apparatus for heating a sample with radiation energy concentrated by a reflector essentially composed of spheroidal surface portions

Abstract: A reflector for use in concentrating radiation energy onto a crystalline sample, comprises two pairs of congruent and coaxial prolate spheroidal surface portions, each of which is disposed outwardly of the other. A predetermined number of confocal prolate spheroidal surface portions may be disposed between the adjacent ends of the coaxial spheroid portions of each pair of spheroidal surface portions, and a pair of hemispherical surfaces may be disposed outwardly of the coaxial spheroidal surface portions. The coaxial spheroids of each pair have a common focus, and the adjacent coaxial spheroids of the respective pairs have a common focus. The foci of the confocal spheroids are coincident with those two foci of the coaxial spheroids of each pair which are conjugate to the common focus of the pair, and the centers of the hemispherical surfaces are coincident with the respective axially outer ones of the conjugate foci. Sources of radiation energy are placed at the respective axially outer ones of the conjugate foci. The sample is placed at the common focus of the spheroidal surface portions.

Semiconductor memory element

Abstract: A semiconductor memory element for use in a memory device having high speed data read out A semiconductor region of one conductivity type is provided on a substrate of an opposite conductivity A first electrode is in ohmic contact with the semiconductor region and a second electrode is coupled to the semiconductor region through a rectifying barrier such as a Schottky barrier or a PN Junction

Gallium-arsenide schottky barrier type semiconductor device

Abstract: A Shottky barrier diode includes a GaAs epitaxial wafer. A Pt-Ni alloy is used as the contact metal to form the Schottky barrier, and an additional alloy layer is formed in the boundary between the Pt-Nl alloy and the GaAs wafer to increase the bonding strength between the wafer and the alloy.

Insulated-gate field effect transistor having gate protection diode

Abstract: An insulated-gate field effect transistor is described which comprises a semiconductor substrate in which an insulated gate field effect transistor, and first and second regions having impurities at a high concentrations are formed. The first region is of the opposite conductivity type as that of the substrate, while the second region is of the same conductivity type as that of the substrate. The second region is in contact with one end of the first region, and the second region and/or the substrate is grounded. The end of the first region in contact with the second region is connected to the gate electrode of the insulated gate field effect transistor, and the other end of the first region is connected to the input electrode.

Strontium niobate electro-optic modulator

Abstract: A single domain crystal of strontium niobate exhibits a substantial transverse electro-optic effect. Intensity, frequency and phase modulators for laser beams, or the like either continuous or pulse, utilizing the strontium niobate crystal may be operated over a broad bandwidth including the visible spectrum at low modulation voltage and power.

Code conversion apparatus

Abstract: Disclosed herein is a code conversion system for converting, in the digital phase, a prediction type first code to a lower frequency, prediction type second code approximating the information content of the first code. In a first embodiment, an input delta modulation code is converted to a lower frequency output delta modulation code, while in a second embodiment, an input delta modulation code is converted to a lower frequency companding delta modulation code.

Device to generate pseudo-random multi-level pulse sequence

Abstract: A device for generating a random pulse sequence provides the randomness of the occurrence of each pulse level in the pulse sequence. In general, it is known that the randomness of the binary pulse train is achieved by logical circuits operating on the Galois field GF(2). However, how to generate a random multilevel pulse train was not known heretofore. The multi-level pulse generator presented here comprises unit delay elements such as flip-flops arranged in a plurality of lines and rows and logical circuits to perform logical operations on the outputs from the unit delay elements on the Galois extension field GF(pk). (p is a prime number) The randomness of this output is mathematically assured.

Automatic chroma compensating system

Abstract: To compensate the chroma component of a color video signal produced by a playback apparatus having a plurality of magnetic heads, the amplitude of selected color burst signals derived from the video signal is detected and stored. At least the first and last signals of each head-channel period are included. A difference signal indicative of the difference between adjacent detected amplitude components is generated, and added to the stored amplitude components to form a control signal. The amplitude of the chroma component of the composite color video signal is varied in response to this control signal.

Pulse regenerative repeater for a multilevel pulse communication system

Abstract: Disclosed herein is a pulse regeneration repeater system which includes means for extracting from a train of multi-level code pulses the clock signal defining the bit interval. Received code pulses, prior to entering a clock signal extracting circuit, pass through a distortion compensating equalizing circuit. The equalizing circuit modifies the pulses in the code pulse train to produce output pulses having a half-level width T'' less than the clock period T, but greater than one-half of the clock period in response to code signals which, prior to transmission distortion, have a half-level width of T/2.

Data handling system for handling data in compliance with normal and special descriptors

Abstract: A computing system in accordance with the present invention processes data in compliance with an instruction and descriptor specified by respective instructions, each descriptor specifying a group of data having at least one characteristic. Each characteristic is composed of an invariable component and, sometimes also, a variable component. Each of the normal and special descriptors includes characteristic information specifying the invariable component. Each of the data and the descriptors includes a tag for determining whether the word is a datum or a normal or a special descriptor. Each instruction including the address of a descriptor further includes, if any, variable information specifying the variable component. The control unit comprises structure for deriving the characteristic from a read-out descriptor, means responsive to the variable information, if any, for modifying the derived characteristic, and means for handling the data in compliance with the unmodified or the so modified characteristic.

Color television camera using only two camera tubes

Abstract: A color television camera employs only two camera tubes. One tube is a color pick-up tube for obtaining a chrominance signal comprising individual signals corresponding to respective two color components of the three primary colors, and the other of which is an image pick-up tube for obtaining a luminance signal. A target for the color pick-up tube comprises a photo-diodearray-type target, and includes apparatus for color separation disposed at the surface of the target on which light is projected, such that the camera optical system may be simplified.

Time division communication apparatus

Abstract: A time division communications system employs central control apparatus for effecting bilateral signaling for a plurality of cascaded system stations. Each station includes receiving and transmitting apparatus for receiving and inserting pulses occurring in a particular time interval of a composite pulse train sequence. The central control unit changes the relative position of the incoming and outgoing pulse digits to effect a desired communications interconnection pattern between the system stations.

Memory circuit employing a bipolar ultrasonic delay line

Abstract: Disclosed is a memory system including an ultrasonic delay line storing data signals having a period T, the data signals being stored as a bipolar signal. The positive and negative peaks of the bipolar signal are sensed to produce peak pulses. These peak pulses are used to generate a replica of the stored data signal. Ambiguous peak pulses are eliminated by passing all peak pulses through inhibit gate means, the gate means being operated to block each of those peak pulses which represents a peak of the bipolar signal occurring within a predetermined time, t, from its adjacent preceding peak. The predetermined time t is selected to be within the range defined as T/2

Temperature compensating circuit for an oscillator

Abstract: An automatic frequency control for a crystal tuned oscillator, comprising temperature sensitive means producing an output voltage varying in magnitude over a predetermined environmental frequency range, a crystal oscillator activated by the temperature means varying output voltage to provide a corresponding output frequency deviation over the predetermined environmental frequency range, and series diodes and capacitors or inductors to compensate for the oscillator output frequency deviation, wherein the diodes are biassed to OFF states by different amounts of voltage to disconnect the capacitors or inductors from the crystal when the temperature means output voltage is less than the biasing voltage smallest amount and further wherein the diodes are activated in turn to ON states to connect the capacitors or inductors in turn with the crystal to maintain the oscillator output frequency deviation at substantially zero value over the predetermined environmental frequency range.

A Doppler RADAR Using a Gunn Diode Both as a Transmitter Oscillator and a Receiver Mixer

Abstract: A simple and low cost doppler RADAR can be constructed by using a Guun diode both as a transmitter oscillator and a receiver mixer. The RADAR has neither a mixer diode nor a circulator. This paper presents analytical and experimental results of the doppler RADAR. A burglar alarm using the RADAR has been developed.

Injection type frequency locked oscillator apparatus

Abstract: An injection-type frequency-locked oscillator provided with novel means for monitoring the operation of the oscillator. An injection input wave is applied through a directional coupler to an auxiliary terminal of the oscillator having a separate output terminal connected to a load. The coupler separates the injection input wave from the oscillator output wave. The output impedance of the oscillator is matched to the load impedance; however, the input impedance of the oscillator at the auxiliary terminal is mismatched to the output impedance of the coupler with respect to the injection input wave, thereby producing in the coupler a reflected injection input wave which is 180 DEG out of phase with the oscillator output wave when the oscillator is frequency-locked at the center frequency of the injection input wave. The signal level at a monitoring terminal of the coupler provides a monitoring signal indicative of the degree of frequency-locking of the oscillator.

Circuit board panel frame construction

Abstract: A frame assembly for mounting a plurality of plug-in circuit board panels includes a frame with a top and base member having engagement edges. Front and rear supporting bars are held in position by the engagement edges at any desired point in the frame, thereby permitting expansion of the panels in accordance with demand. Guide plates having grooves and central cooling apertures support the panels, and in turn, are supported by the front and rear supporting bars.

Segment type display tube for selectively displaying one or more of a plurality of alpha-numerical characters

Abstract: A display tube for use in displaying various characters comprises an electrode assembly sealed in a container. The electrode assembly has a first electrode and a set of character segment electrodes. The tube further comprises a first stem lead connected to the first electrode and a set of second stem leads connected to the set of character segment electrodes, respectively through a set of lead-wires. The set of lead-wires are secured to an insulator frame means defining an opening providing a discharge space so that the set of character segment electrodes may be arranged in one common plane in the opening. The lead-wires and second stem leads may integrally extend from the character segment electrodes.