Abstract: A source coil line-break/short-circuit detecting circuit and a probe connection detecting circuit are provided to the source coil driving circuit unit of an endoscope shape detecting apparatus. The source coil line-break/short-circuit detecting circuit detects line-breaks and short-circuits of the source coils. The probe connection detecting circuit detects whether a connection exists with a probe. A marker coil line-break/short-circuit detecting circuit detects line-breaks and short-circuits of the marker coils. A marker connection detecting circuit detects whether a connection exists with a marker. Accordingly, using the apparatus without being connected to a probe or markers can be avoided by detecting the connection of the probe and markers by the probe connection detecting circuit and marker connection detecting circuit, respectively, when the system is energized, thereby avoiding detecting noise and consequently displaying a random image on the monitor.

Abstract: A pump control means controls a fuel pump so that fuel pressure supplied into the internal combustion engine becomes lower than a predetermined fuel pressure regulated by a fuel pressure regulator when the operating state of the internal combustion engine is within a predetermined operating state. Thus, the fuel pressure has already been controlled low while the engine state is within the predetermined operating state, so that the fuel leak from the injector during an engine stop is suppressed, thereby reducing an exhaust of deleterious gas when the engine starts again. Further, since the fuel pressure is decreased while the engine works, electric power is not wasted for decreasing the fuel pressure.

Abstract: A pump control means controls a fuel pump so that fuel pressure supplied into the internal combustion engine becomes lower than a predetermined fuel pressure regulated by a fuel pressure regulator when the operating state of the internal combustion engine is within a predetermined operating state. Thus, the fuel pressure has already been controlled low while the engine state is within the predetermined operating state, so that the fuel leak from the injector during an engine stop is suppressed, thereby reducing an exhaust of deleterious gas when the engine starts again. Further, since the fuel pressure is decreased while the engine works, electric power is not wasted for decreasing the fuel pressure.

Abstract: A multi-degree-of-freedom manipulator includes a flexible tube having a plurality of flex portions provided therealong, a plurality of actuators made of shape memory alloy and respectively provided near the flex portions to correspond to the flex portions, for flexing the flex portions, two common energy transmission paths, extending along the flexible tube, for transmitting an energy to the actuators, and selective energy supply members, provided between the common energy transmission paths and the actuators in series, for controlling the energy supplied from the common energy transmission path to the actuators, thereby respectively independently driving the actuators to bend the flexible tube.

Abstract: A multi-degree-of-freedom manipulator includes a flexible tube having a plurality of flex portions provided therealong, a plurality of actuators made of shape memory alloy and respectively provided near the flex portions to correspond to the flex portions, for flexing the flex portions, two common energy transmission paths, extending along the flexible tube, for transmitting an energy to the actuators, and selective energy supply members, provided between the common energy transmission paths and the actuators in series, for controlling the energy supplied from the common energy transmission path to the actuators, thereby respectively independently driving the actuators to bend the flexible tube.

Abstract: A bending drive member to bend a bending member is arranged to extend in the direction of length of an elongate tube having flexibility, and attached to near the distal end of the tube with the distal end of the bending drive member being restricted in its position. The bending member drive member comprises a shape memory member formed by bundling together a plurality of wire-like shape memory materials each having a length, that spans from the position of one end to the other end, reversibly changed upon heating/cooling. The length of the shape memory member is changed dependent on a drive signal from a unit with a capability of heating. A non-compressive coil sheath through which the bending drive member extends is fixed at a distal end thereof to the elongate tube while the proximal end of the coil sheath is a free end with respect to the elongate tube.

Abstract: In a frequency division multiple access (FDMA) communication system, a plurality of carrier frequencies relating to a predetermined frequency band for transmitting a PSK (phase shift keying) signal are provided on a frequency scale. When a service is a low bit rate signal, it is transmitted by using a single carrier frequency and its related frequency band. When a service is a high bit rate signal which can not be transmitted in a single carrier signal, the service signal is divided in to a plurality of low bit rate PSK signals, each of which is transmitted by using a single carrier frequency and the related frequency band.

Abstract: A Viterbi decoder synchronization circuit comprises a phase shifter for introducing a variable amount of delay time to a received bit stream of convolutional codes in response to a control signal applied thereto with respect to a word synchronization signal which is derived from the bit stream. A first detector detects maximum and minimum metric values of the Viterbi decoder. A second detector detects the difference between the detected maximum and minimum metric values for coupling to an integrator. The output of the integrator is applied to a third detector which detects when the integrator output reaches a value indicative of a word-in-sync or word-out-of-sync condition. A phase shift signal is generated in response to an output signal from the third detector and applied to the phase shifter as the control signal.

Abstract: A Viterbi decoder synchronization circuit comprises a circuit that derives a word synchronization signal from a received bit stream of convolutional codes. A first detector detects a maximum of metric values derived from the Viterbi decoder at different locations in time. A memory is provided for storing therein the address codes derived at different times and the maximum metric values detected by the first detector. A second detector is connected to the memory for detecting the presence of a path between the states addressed by the address codes stored in the memory. An integrator is connected to the second detector to integrate its output signal. To the integrator is connected a third detector which detects when the integrator output reaches a value indicative of one of word-in-sync and word-out-of-sync conditions of the Viterbi decoder. A phase shift signal is generated in response to an output signal from the third detector and applied to a phase shifter to introduce a delay time to the bit stream.

Abstract: A maximum likelihood error correcting technique for a digital communication in which a transmit side provides coded data with some redundancy through a convolutional coding circuit, and a receive side corrects transmission errors automatically through a maximum likelihood error correcting circuit has been improved by deleting some symbols at a transmit side to increase a coding rate close to 1, and inserting dummy symbols at a receive side into each bit position where a symbol has been deleted at a transmit side. A likelihood value for that dummy symbol inserted at a receive side for the maximum likelihood decoding is a fixed predetermined value. Thus, both a coding circuit in a transmit side and a decoding circuit in a receiving circuit have only to handle original low rate code, while keeping a coding rate in a transmission line high.

Abstract: A satellite repeater for a digital satellite communication system for use on board of satellites. Receivers are provided with respective antennas for receiving radio-frequency signals from a plurality of ground stations. A signal processing circuit switches signals received in synchronism with stable clock timings. Transmitters receive the switched outputs of the signal processing circuit to provide radio-frequency signals for transmission through respective antennas of the transmitters. Timing detectors receive the outputs of the receivers and detect the frame timings of the output signals of the receivers. Signal storage circuits are provided between respective outputs of the receivers and the signal processing circuit for storing the respective output signals of the receivers by respective amounts.

Abstract: A system for compensating for cross polarization coupling in a dual-polarization satellite communication system, in which two polarized waves of the same frequency and orthogonal to each other are alternately transmitted as a pilot wave from an earth station at a predetermined period. The same polarized wave components of the two signals received by a communication satellite are sent back to the earth station, so that the sent back signal is received by the earth station. An amplitude ratio and a phase difference between the same polarized wave components of the two signals of the received pilot signal are detected. A communication signal wave to be transmitted from the earth station is formed as an elliptically polarized wave by the use of the detected information, thereby compensating for cross polarization coupling of the communication signal wave caused during propagation between the earth station and the communication satellite.

Abstract: A transmultiplexer, in which after a pulse code modulated, time division multiplex signal of the voice band signal is converted into an analog signal, the analog signal is separated by filters into signals of respective channels and then the signals of the respective channels are combined together to provide a single sideband frequency divided, multiplex signal. In a reverse signal flow type, after a single sideband frequency-divided multiplex signal is separated by filters into signals of respective channels, the signals of respective channels are converted into digital signals and thereafter combined together to provide a pulse code modulated, time division multiplex signal. In accordance with this invention, a sign bit inverter is provided for reversing sign bits of predetermined specific channels in the pulse code modulated, time division multiplex signal every other frame.

Abstract: A system for controlling teletype signals, in which a start-stop telegraph signal train may be received at the reversed polarity state. The polarity of a signal element of a received character is decided at a specified instant in a time slot at which the stop element of the received character is expected to arrive. The polarity of a signal element of the received character is again decided in a time slot at which a stop element after a predetermined number of characters from the specified instant is expected to arrive. Only when the polarities of the signal elements of the received characters are decided as the same A-polarity during both of the decision operations, the polarity of the telegraph signal train is automatically reversed.

Abstract: A system for determining burst sending timing in a time division multiple access communication system using a communication satellite, in which burst signals transmitted from a plurality of stations are arranged on the communication satellite in one frame at predetermined intervals. On the transmitting side connected to the communication satellite through a radio wave path, a first signal composed of a first signal state over one frame length defined by the sending frame timing is sent, and then second, third, fourth, . . . signals each composed of the first signal state and a second state different from the first signal state are sent. In this case, the position or length of the first signal state in one frame is altered by a certain amount.