Abstract: Modularly Structured Digital Communications system. The multi-tasking operating system of a central system processor control administers a line technology task having device program modules associated with types of terminal equipment and administers a switching technology task having switching procedure program modules independent of the class of terminal equipment and independent of communications service. The line technology task and the switching technology task each have input and output memories operated mailbox like allocated to them. For exchange of messages between the tasks, the multi-tasking operating system have a program bus structure with a transmission protocol defined with universal validity independently of communications service and independently of type of terminal equipment.

Abstract: A digital switching network is disclosed in which paths can be preset from any inlet to any outlet either for circuit-switched connections or for packet-switched messages (packets), as required. At any point in time, the paths preset for the packet-switched messages form a network whose nodes lie in the switching facilities of the switching network. The switching facilities contain the functional units required to switch each data packet on the path preset for it. This makes it possible to dynamically divide a single switching network into a circuit-switching network and a packet-switching network as required.

Abstract: In an optical heterodyne homodyne detection apparatus, signal light and local oscillation light are combined, and the combined light is received in an optical detector to produce intermediate frequency signal which is then demodulated thereby producing base band signals. The frequency sweep of the intermediate frequency signal is performed so that the frequency of the intermediate frequency signal becomes a predetermined value. During the frequency sweep, at least one polarization of the signal light and the intermediate frequency signal is scrambled, and is stopped when the frequency becomes the predetermined value. Thereafter, polarizations of the signal light and the local oscillation light are coincided with each other in accordance with the polarization angle control.

Abstract: A tuner with a timepiece for a watch radio includes a display on which either a current time being counted by the timepiece or a frequency being received by the tuner is selectively displayed, and a first key group including a plurality of keys which are operated to control a function of the timepiece and a second key group including a plurality of keys which are operated to control a function of the tuner. An operation of the second key group is inhibited when the current time is displayed on the display. In this state, a displaying state of the display is automatically changed and the frequency is displayed on the display if a band key included in the second key group is operated, and thereafter the operation of the second key group is allowed to control the function of the tuner.

Abstract: A communication system having a base station and a number of field units employs a virtual hold technique and a self-testing technique. In the virtual hold technique, when a field unit is put on hold, the communication channel previously used by the field unit is released for use elsewhere in the system, thereby increasing the efficiency of the system. In the self-test technique, a test signal is transmitted to the field unit where it is applied to the earpiece of a handset so as to generate sound waves which are picked up by the microphone in the mouthpiece of the handset and transmitted back to the base station for comparison with the original test signal. In this manner, the entire communication loop is tested without the need for human intervention, and in particular without the need for a person to be present at the field unit. The self-test technique improves the reliability of the system.

Abstract: A fiber-optic switch uses a single optical fiber for two-way communication with light. A switching mechanism has no electrical part and is thus appropriate for placement in an area having explosive or combustible material. The optical fiber can be cut to length in the field and can be installed without special tools or training. The fiber is held in place by a clip that is constrained to compress the fiber and grip it securely. A snap-action mirror reflects light back into the fiber in one position and does not reflect it in another position. An electronic circuit provides pulsed light and determines coincidence of sent and received pulses to discriminate against operation of the switch by ambient light or other spurious signals.

Abstract: A portable wireless communication apparatus of new type is provided. The apparatus is composed of a handset type substantially parallelopiped body which is to be used in combination with a battery pack in a portable mode and a support tray installed in a passenger car room for hand-free use. The top surface of the body is provided with a key operating section, a display section and a speaker. All of them are in the user's sight while the apparatus is being used in the hand-free mode. In the portable mode, on the other hand, all the user has to do is only take up the apparatus away from the tray after the key board operation, hold the receiving section against the ear and talk into the transmitting section without changing the grip.

Abstract: An improved stabilizing device incorporated into a socket-adapter for miniature fluorescent lamps includes a square-shaped iron core member with a coil arrangement provided therearound so as to form a required stabilizing device with a square open section defined in a middle portion for accommodating a socket seat of the socket-adapter for known miniature fluorescent lamps. The iron core member is composed of a plurality of L-shaped silicon steel laminated cores, and the coil arrangement includes a plurality of coils wound around a plurality of I-shaped coil frames, each of which has a through opening in a middle portion for being sleevingly installed around both arms of the L-shaped laminated cores so as to form a square open section in the middle of the iron core for accommodating the socket seat of the socket-adapter. Thereby, the total volume of the socket-adapter stabilizing device is substantially decreased.

Abstract: Intermediate frequency signals are produced by mixing with an oscillator voltage and subsequently filtered and demodulated. The oscillator voltage or the resonance frequency of the filter or filters are followed up by a control voltage derived from the demodulated signal corresponding to the intermediate frequency. The perturbatory phase modulator occurring as a result of the control lag is compensated by opposite-phase phase-modulation which is superimposed on the intermediate frequency. In this, the phase modulation is achieved by a phase modulator which is connected with the output of a demodulator by a matching circuit. Another possibility for achieving phase modulation of the intermeidate frequency is to modulate the oscillator of the mixing stage.

Abstract: An intrusion detection optical communication system modifies the original data signal to include a synchronizing periodic waveform. The receiver generates an inverted synchronizing periodic waveform signal corresponding with the transmitted signal to null the same under normal operation. When an intrusion in the optical system arises, power is extracted from the system and the nulled condition is disrupted. The disruption is detected and activates an alarm circuit when the disruption is above a threshold value.

Abstract: A receiver includes a signal-receiving section for receiving input signals and outputting detection signal, and a power source for supplying power thereto. A first detector detects a preamble of each input signal while a second detector detects the end of a postamble of each input signal. A power supply section supplies the power to the signal-receiving section by turning on a switch connected between the signal-receiving section and the power source when the first detector detects the preamble of the input signal. A periodic power-supply section turns on the switch periodically to supply the power periodically to the signal-receiving section when the second detector detects the end of the postamble of each input signal.

Abstract: A detachable battery pack with a built-in broadband antenna is disclosed. Since the antenna is wholly contained within the battery housing, it is protected from damage and is detachable from the transceiver when the battery is detached. A transmission line structure formed between the battery and the transceiver is used to create an open circuit near the antenna feed point.

Abstract: In a time division multiple access satellite communications system having a master station and one or more remote stations, frequency offset through the translation oscillator in the satellite is corrected by transmitting a pilot frequency signal, reference to a high precision oscillator, through the satellite, so as to subject the pilot frequency signal to a frequency translation and monitoring the frequency translation of the pilot frequency signal as received at the master station subsequent to its transmission through the satellite. Signals to be transmitted over the satellite communications link from the master station to remote stations are subjected to a frequency translation that is effectively complementary to the monitored frequency translation.

Abstract: Disclosed is a dense channel packing wavelength division multiplexed optical fiber communication system that is parsimonious in its cable length requirements and that does not require the presence of widely tunable lasers at the remote terminals. The system comprises a central station and N remote stations (N frequently greater than about 50) connected to the central station by optical fiber means that comprise a "backbone" and l (1<l<N) fiber "laterals". Associated with each remote station RS.sub.i is a predetermined wavelength .lambda..sub.i, typically in the spectral region 1.25-1.6 .mu.m. The central station comprises means adapted for generating electromagnetic radiation of a multiplicity of distinct wavelengths including all .lambda..sub.i. The radiation from the central station is coupled into the backbone fiber and transmitted to the laterals and the remote stations. Each remote station RS.sub.i comprises means for selecting the radiation of the associated wavelength .lambda..sub.

Abstract: In a gas discharge display panel, first and second driving electrodes are capacitively coupled to each display electrode on at least one of two substrates. The first and second driving electrodes of the display electrodes are formed by a first group of driving electrodes and a second group of driving electrodes by connecting the first and second driving electrodes as a plurality of groups. Specified display electrodes are controlled by selecting the first and second electrodes at the same time. The method for driving the gas discharge display panel includes the steps of discharging all dots in one selected line of the discharge electrodes which are to be written, and of erasing selected dots which are not to be written.

Abstract: The present invention describes a phase shift key receiver or demodulator having an A.C. couple base band automatic gain control. A pair of detectors for the automatic gain control are A.C. coupled to the output of a pair of linear analog multipliers for the purpose of eliminating DC offset signals and for minimizing thermal noise at the input of the automatic gain control circuit. The outputs of the pair of detectors connected in the data detecting branch and the carrier tracking branch of the PLL are connected to a input of the summing circuit whose output is connected to the automatic gain control loop filter. The output of the filter supplies the scaling signal employed as the scaling input to the linear analog multipliers.

Abstract: The Invention provides a locally distributed crossbar switch to optically connect many computer processors and memories in arbitrary permutation an without interruption. A process or and an associated memory can be packaged together, taking advantage of the fact that the distributed crossbar switch employs local switching. At the same time, processor-memory pairs can be physically separated from other such processor-memory pairs, and by great distance.

Abstract: The present invention relates to a communication method using a small-scale computer network and a communication equipment used therefor. Particularly, a novel communication method in a communication equipment is capable of accumulating a plurality of communication data, i.e., frames at the same time and having a function to sequentially transmit them to the network. According to this method, after transmission of a single frame is completed, when the condition is satisfied that a predetermined time has passed or the condition that the transmission of the frame from any other communication equipment is completed, transmission of the next frame is initiated. Accordingly, this method eliminates the possibility that solely a specified communication station occupies the network, thus making it possible to improve efficiency in use of the network.

Abstract: A satellite communication system includes a plurality of mobile stations which are situated on the earth and a communication satellite which is communicable with the mobile stations by radio signals over a plurality of spot beams. The satellite applies single sideband amplitude modulation (SSB-AM) to analog signals which are sent from the mobile stations, applies digital modulation to coded voice and data, and separates signals in the form of frequency-division-multiplexed (FDM) signals on a channel basis by a transmultiplexer method which is implemented by demultiplexers of a transponder. Baseband matrix means is provided for connecting an output of any of the demultiplexers to one of the spot beams to be transmitted. Further, transmitting means is provided for time-division-multiplexing outputs of the baseband matrix means to form a transmit frame and transmitting it in the form of a TDM signal.

Abstract: Apparatus and method for amplitude equalization of a signal channel such as a telephone line that does not require adjustments at the customer's premises. The equalization circuit receives a plurality of alignment signals at predetermined frequencies from the signal channel, and measures the amplitude of each alignment signal. The amplitudes are used to determine analog and digital filter transfer function coefficients. Thereafter, input signals on the signal channel are filtered such that the combined amplitude response of the signal channel and filter is substantially flat over a designated frequency range.