Abstract: A response permission command is transmitted from a reader/writer, thereby setting all of data carriers to a response possible state. Subsequently, a data return command is transmitted, thereby returning data for collation on a bit unit basis. The reader/writer transmits a data collation command of, for example, bit 0 to each of the data carriers when recognizing the return of the data in which bits 0 and 1 mixedly exist. When an own return bit coincides with a collation bit, each of the data carrier judges that the collation succeeds and returns a next bit for collation. When they don't coincide, however, a state of the data carrier is switched to a response inhibition state. By repeating such processes with respect to all of the bits of the data for collation, only one data carrier finally remains in a response possible state and generates an access permission command, thereby performing the reading or writing operation.

Abstract: A plurality of data carriers are prepared and possessed by, for example, persons who enter a building. The data carrier spread spectrum modulates a carrier signal of a predetermined frequency by an assigned Gold series corresponding to an ID code and transmits the modulated signal. Leaky cables each having a predetermined length are two-dimensionally distributed and arranged in the building. A frequency converter is connected to one end of each of the leaky cables and frequency converts the spread spectrum signal from the data carrier which has propagated the leaky cable into a frequency unique to the cable and sends the converted frequency signal to a central receiving unit through a transmission cable. The receiving unit individually demodulates the signal series from the reception signals and sequentially executes correlation calculations between the signal series and the Gold series assigned to the data carriers.

Abstract: Bidirectional transmission of write and read data is effected between a reader/writer unit and a memory module in a contactless manner using electromagnetic induction coupling. A single magnetic induction coupling apparatus is provided for each of the reader/writer unit and the memory module. In the electromagnetic induction coupling apparatus of the reader/writer unit, a transmitting coil and a receiving coil are coaxially wound around a single magnetic core. In the electromagnetic induction coupling apparatus of the memory module, a single coil which is commonly used for transmission and reception is wound around a single magnetic core. A reception signal of the transmitting/receiving coil of the memory module is rectified and smoothed by a power source circuit, thereby forming an operating power source of the memory module. The power source circuit has a backup capacitor.

Abstract: In response to a bit transfer request from one of two units, bit data is transmitted bit by bit from the other of the two units. The unit on the transmission side for transmitting the bit data has an M-series generator. In response to bit 1, a first M.sub.0 -series signal of a 63-word length is generated. In response to bit 0, a second M.sub.0 -series signal in which the series start position is set to the intermediate position of the first M.sub.0 -series signal, although the signal is the same M.sub.0 -series signal of the 63-word length, is generated. The unit on the reception side has previously stored the first and second M.sub.0 -series signals on the transmission side as reference signals, and calculates the correlations between the two reference signals and the reception signal, and demodulates the data bit corresponding to the reference signal having a larger correlation value.

Abstract: A control signal used to write access or read access and data are transmitted between a write/read unit and a memory module by a contactless coupling using induction coils. The write/read unit multiplexes a control signal consisting of three signals including a power source signal, sync clocks, and enable clocks using frequency modulation and supplies the resultant multiplexed signal to one end of the induction coil for transmission. The write/read unit frequency modulates access data and supplies same to the other end of the same induction coil for transmission. The transmitting coil in the memory module allows the signal which is obtained by adding an access signal to the control signal to be induced in the coil for reception in the write/read unit. The read data from the memory module is frequency modulated and sent from the memory module to the write/read unit by using the transmitting and receiving coils for a down-signal which is used only to read out data.

Abstract: A tool holder is enclosed in a rack which is moved by a belt for automatic tool exchange. A stopper member provided for the rack is fitted into a positioning groove formed in a flange portion of the tool holder, thereby preventing the rotation of the holder. A magnetic induction coupling apparatus is buried in the bottom of the tool holder positioning groove. A magnetic induction coupling apparatus of a reader/writer disposed at the external position is arranged so as to face the magnetic induction coupling apparatus of the tool holder. Information is written into or read out of a memory module attached in the tool holder by way of the magnetic induction coupling between both of those coupling apparatuses. The stopper member of the rack is arranged between the magnetic induction coupling apparatus of the tool holder and the magnetic induction coupling apparatus of the reader/writer and has a magnetic material to magnetically couple these coupling apparatuses.

Abstract: The bidirectional transmission for reading and writing data is performed between a write/read unit and a memory module using the contactless induction coupling of induction coils. The write/read unit frequency multiplexes a power source signal, a sync clock, and an enable clock and transmits the frequency multiplexed signals to the memory module. The memory module rectifies the received frequency multiplexed signals to produce an operating power source and to reproduce the sync clock and enable clock and to form an enable signal from the OR of both clocks. The write and read access information transmitted through another route is read in response to the reproduced sync clock and enable signal, thereby executing the writing and reading operations of a non-volatile memory.

Abstract: A memory module is attached to a pallet having at least one workpiece thereon. Machining processing data of the at least one workpiece is written into the memory module of the pallel put on a pallet yard. When the pallet is moved to a machine tool, the work machining processing data stored in the memory module is read out and set into a controller of the machine tool. Data is written into or read out from the memory module in a contactless manner by using induction coupling coils.

Abstract: The driving speed of a hydraulic actuator is feedback controlled by adjusting an amount of fluid by a digital valve having a valve which is opened and closed by a pulse motor. For speed control, the deviation between a set speed of the actuator which is set by a speed setting device and a detection speed of the actuator which is detected by a speed sensor is obtained. A pulse signal of a frequency proportional to the magnitude of the deviation is generated. When the deviation is positive, the pulse motor is driven using the pulse signal as a CW command pulse. When the deviation is negative, the pulse motor is driven using the pulse signal as a CCW command pulse. The rotational amount of the pulse motor is the integral of the pulse frequency which is proportional to the deviation.