Abstract: An electrical contact material and method of producing the same are provided. The material is an internally oxidized silver eutectic alloy system with a main component of silver to which at least one of silicon and germanium is added and, for characteristic improvement purpose, at least one selected from at least one of the groups consisting respectively of gold, platinum and the like, titanium, rhenium and the like, and iron, cobalt and the like is further added. In producing the material, an ingot of said alloy is hot-worked and then internally oxidized at a temperature in a range from 250.degree. C. to the eutectic temperature of the alloy.

Abstract: In a diffraction grating made of a single crystalline silicon substrate, one major plane thereof is provided with a plurality of asymmetric triangular grooves, each having a wall inclined by an angle .theta. with respect to the major surface so as to satisfy an equation ##EQU1## where .theta. represents the blaze angle, P the pitch of the groove, .lambda..sub.B the blazing wavelength, and m the order of diffraction. The walls of each groove receiving incident light is covered with a metal coat.The diffraction grating is prepared by using a {hkl} plane (where h=k) inclined by .theta. with respect to the {111} plane of the single crystalline silicon as a major surface, and then anisotropic-etching the major surface through an etching mask having stripes having sufficiently smaller width than the grating constant. Preferably, following the anisotropic etching, isotropic etching is made for the major surface.

Abstract: A method of manufacturing a field effect transistor uses a semiinsulating substrate consisting of a compound semiconductor, and an N type semiconductor layer formed on the substrate. The method comprises the steps of implanting ions of a P type impurity from the main surface of said semiconductor layer to form at least two P type gate regions which extend from the main surface to substantially reach said substrate and are disposed with a predetermined interval, and sintering metallic layers on the gate regions in ohmic contact and on opposite sides of the semiconductor layers with said semiconductor gate regions being interposed therebetween to form a gate, a source and a drain electrodes. Said implantation step further comprises a step of positioning at least two of said gate regions such that said gate regions come in contact with the boundary region of the transistor to be constructed.

Abstract: A system for simultaneously transmitting over the same voice circuit a voice signal and input information other than the voice. First and second sine-wave signals which do not bear any harmonic relation to each other in the band of the voice circuit are simultaneously frequency modulated by the input information, and the modulated outputs are superimposed on the voice signal and transmitted. On the receiving side, the pitch frequency of the voice signal is extracted from the received signal, and the pitch frequency and its integral multiples are removed from the received signal to remove a voice component. At this time, at least one of the first and second sine-wave signals is detected. One of these detected outputs is made to have the same frequency as the other frequency. The converted frequency and the detected frequency are demodulated to obtain the original input information.

Abstract: A space diversity reception system which minimizes the inband amplitude and/or phase dispersion by controlling the phase shifter is described. According to the present invention, the interference waves in the two antenna outputs are combined in anti-phase condition. The phase shifter control direction is decided by the sign of the two parameters. One of them is difference between two antenna levels at the center frequency of the pass-band, and the other is the difference of the combined signal levels at the extreme edges of the pass-band. The control means comprises four detectors for detecting said levels, two subtractors for providing said level difference between them, and the control circuit for deciding the phase shifter control direction.

Abstract: An apparatus for selectively granting priority use of telephone lines to a telephone or data transmitter each connected via the telephone lines to an exchange center. Access of the data transmitted to the exchange center is typically enabled by application of DC voltage of a predetermined polarity to the telephone lines by a control circuit. A current detection circuit is provided in series with the telephone for detecting when the telephone lines are providing current to the telephone during a time when the date transmitter is transmitting or receiving data via the telephone lines. In the event that the current detection circuit detects a current component on the telephone lines to the telephone, application of power to the data transmitter is stopped and priority use of the telephone lines is granted to the telephone.

Abstract: A coordinate input apparatus. A pair of optical guide channel arrays each including a required number of parallel optical guide channels (11, 12) which contain optical scatterer (22) are superposed to form an input board (100) with the optical guide channels of the two arrays intersected at right angles. Light is detected which is scattered by the optical scatterer (22) in the optical guide channels (11, 12) corresponding to irradiation of one point on the input board by a light pen (10) and reaches end surfaces (11a, 12a) of the optical guide channels. The detected signals are processed to form a binary signal train representative of the coordinate of the light pen (10).

Abstract: This invention relates to a pattern-forming process using a radiation sensitive chalcogenide layer composed of a laminate of amorphous chalcogenide layer (2) and thin silver layer (3), and discloses a pattern-forming process characterized by etching out an amorphous chalcogenide layer (22) not doped with silver at an unexposed area under an irradiation of a light (6) or an accelerated corpuscular beam by a plasma etching with a fluorine-series gas and also a pattern-forming process wherein silver-doped amorphous chalcogenide layer (21) left on the substrate according to a given pattern by the above process is used as an etching mask and then the substrate layer (1c) is etched out by a plasma etching to form the given pattern on the substrate.

Abstract: The error rate performance of a digital radio system which is deteriorated due to inband interference components can be effectively improved by adopting the present digital signal reception technique. According to the present invention, a narrow band band-elimination filter removes the interference, and after the digital signal is regenerated, the spectrum, which is removed by said band-elimination filter, is recovered from the regenerated digital signal. The recovered digital signal is added to the original one, and is applied to the regenerator. Thus, even though an interference component interfers with the digital signal in the same pass-band, said interference component is removed by the present invention and one can obtain the digital signal without the interference component.

Abstract: A three-terminal power supply circuit for telephone set has an input terminal, an output terminal and a common terminal. The input terminal receives a DC voltage superposed with a sending or receiving signal transmitted to or from a telephone station through a subscriber line. The output terminal delivers DC power to a telephone circuit. Between the input and output terminals a constant current circuit and a discharge protection circuit are connected to each other in series. Between the output terminal and the common terminal a constant voltage circuit is connected. Between the input terminal and the common terminal an electronic switch is connected through the constant current circuit. The electronic switch is closed only when an instantaneous voltage applied between the input terminal and the common terminal is lowered to a predetermined value or a lower value. When it is closed, the electronic switch causes a short circuit in the constant voltage circuit through discharge protection circuit.

Abstract: A color picture is separated into three color component pictures, which are divided respectively by first, second and third block coding means into blocks and encoded. In the first block coding means, one of the color component pictures is encoded, for each block, into gray level codes representing gray level components in the block and a resolution code representing the distribution of the gray level codes in the block. In this case, when the gray level in the block undergoes a little change, an average gray level can be used as the gray level code and the resolution code can be omitted. The second and third block coding means may be identical in construction with the first block coding means. The resolution code of the block obtained by the first block coding means can also be employed in the coding of the corresponding blocks by the second and third block coding means.

Abstract: The input surface of the apparatus for detecting X and Y coordinates of the input points comprises a first parallel electrode group, a second flexible parallel electrode group opposing and intersecting the first parallel electrode group. A pressure conductive rubber sheet which becomes conductive when the pressure is applied to the input surface is interposed between the two electrode groups. First and second resistors are provided which are in electrical contact with terminal ends of the two electrode groups. Electric signals from the first and second resistors are used to detect X and Y coordinates of input points on the input surface.

Abstract: A data transmission system wherein a transmitter always transmits the carrier to a receiver and modulates the carrier by using the sending data and a receiver demodulates the sending data, wherein, in order to discriminate whether the data demodulated in the receiver is sending data or not during an existing sending data period, the transmitter converts specified bits of sending data and then transmits and the receiver discriminates the sending data existing period according to detection of such conversion being carried out.

Abstract: A tunneling Josephson junction is disclosed in which first and second superposed superconducting electrode layers are formed of thin films of oxide superconducting materials having a perovskite structure of BaPB.sub.1-x Bi.sub.x O.sub.3. A barrier layer interposed between these superconducting electrode layers is a thin film of long service life which is stable and breakdown free under heat cycles from room temperature to ultra low temperatures. This film is made of an oxide with perovskite structure which has the same crystal structure and thermal expansion coefficient as those of the first and second superconducting layers for functioning as an insulator or a semiconductor. The oxide with perovskite structure may be BaSnO.sub.3, Ba.sub.1-y Sr.sub.y Pb.sub.1-x Bi.sub.x O.sub.3 (wherein 0.ltoreq.x.ltoreq.0.3, y>0.3) or BaPb.sub.1-x (A.sub.1-y Bi.sub.y)O.sub.3 (wherein A is at least one member selected from the group consisting of V, Nb, Ta and Sb; 0.1.ltoreq.x.ltoreq.0.3; and 0.ltoreq.y.ltoreq.0.5).

Abstract: A current supply circuit for a telephone exchange is disclosed in which a current-supplying current amplifier series-connected between a power supply and a load amplifys an output current of an input current supply circuit, and a driving current amplifier for driving the current-supplying current amplifier is controlled by an output of an output voltage detector parallel-connected with the load in a negative-feedback fashion to set the differential mode output impedance of the current supply circuit at a large or small value in accordance with frequency and to set the common mode output impedance at a small value; and in which a part of the output voltage detector for connecting the load to the driving current amplifier includes a diode for preventing a direct current from flowing in a opposite direction to that of a direct current from the power supply in order to suppress, independently of the state of the load, a current which flows from the load side into the driving current amplifier, whereby an increase

Abstract: A synchronization system for a key telephone system, in which key information or the like information signal between a key service unit and each key telephone set is transmitted in the form of a time-division pulse signal under the control of a counter provided in the key service unit. The information signal has a format which is divided into a first signal from the key service unit to each key telephone set and a second signal from each key telephone set to the key service unit so as to make distinction between the first and second signals in terms of time. The first signal is disposed in a time slot preceding the second signal to provide a pair of signal groups. A one-pulse start signal is disposed in the foremost time slot of the signal groups and a one-pulse answer signal is disposed in a time slot between the first signal and the second signal.

Abstract: Glass for optical fibers is made of material of a binary system containing a fluoride selected from BaF.sub.2, SrF.sub.2 CaF.sub.2 and PbF.sub.2 and another fluoride selected from AlF.sub.3 and ZrF.sub.4.

Abstract: In a magnetic memory device wherein a magnetic recording medium is rotated in a substantially closed chamber, there are provided a throttle between the inside and outside of the chamber, a first air fliter for filtering air flowing through the throttle to prevent moisture from entering into the chamber by diffusion, a container containing a desiccating agent and communicated with the chamber, and a second air filter located between the desiccating agent container and the chamber. In a modified embodiment, another throttle is also provided between the desiccating agent container and the substantially closed chamber.

Abstract: The invention relates to a single-mode optical fiber used in a long wavelength band range for optical telecommunication. The core and the cladding of this optical fiber contain P.sub.2 O.sub.5 as a dopant selected to lower the deposition temperature and to hasten the deposition speed so as to result in low absorption loss.

Abstract: A pulse or stepping motor with a stator assembly and a rotor assembly has been found. The stator assembly comprises a cylindrical housing of ferromagnetic material, the first, second, third, and fourth ring shaped stators secured in said housing with some gaps between them, a pair of circular windings secured between the first and the third stators and between the second and the fourth stators respectively, the axis of said winding being identical or parallel to the axis of the pulse motor itself, each of said stators having a plurality of magnetic poles on the inner surface of the ring shaped structure, the angular duration of each magnetic pole of each stator being of uniform pitch.