Sharp Kabushiki Kaisha Corporation

Toshiyuki Matsubara

Hidehiko Tanaka

Masahiro Ise

Katsuyuki Machino

Teiji Terasaka

Takaaki Okamoto

Katsuyuki Machimno

Hasahiro Ise

A very useful data transmission system having a plurality of transmission modules connected to a single cable in a multidrop manner is disclosed herein. The system features its ability to check the transmission state at the level of individual modules through use of a proper code notation (typically, Manchester code). The system detects a specific module with proper signals lasting at the same level for more than a given time, except cable outputs, and treats it as involving a faulty condition and compels the transmission state to a halt, thus preventing only the faulty module or modules from transmitting signals thereby avoiding breakdown of the whole system.

Data transmission system

The present disclosure is directed to an emergency access method in which in the event that an emergency data occurring at a particular terminal is fed immediately to a central system but collides with any emergency data from a different terminal such collision is sensed and a signal in that data is delayed in a random number manner through the use of an appropriate random number generating algorithm in order to avoid such collision within a short length of time.

Emergency access method in centralized monitoring system

A data transmission method over building wiring includes a plurality of transmission sections. One of these sections is selected from the plurality of transmission sections to be a data transmission source machine for providing data. The data is transmitted from the data transmission source to the remaining transmission sections. If a transmission section is not selected it is used to relay the data to one of the remaining transmission sections wherein it is received by a final data transmission section. A data transmission section used in the method, comprises a data receiving part for receiving the transmitted data, a relay counter part for counting the number of relaying the transmitted data, and data relaying part for steps of relaying the-received data.

Data transmission system over building wiring

A signal transmission system utilizes the building or house wiring as the data transmission line. A frequency detection system is required to detect a frequency of the power voltage. The frequency detection system includes a zero-crossing detection circuit for developing a detection output when the zero-crossing is detected. A timer element is provided in the frequency detection system, which functions to neglect an output signal from the zero-crossing detection circuit for a preselected period of time after the last detection output has been developed from the zero-crossing detection circuit.

Power frequency detection system

A data transmission system for transmitting and receiving data over a transmission line includes a receiving station having a receiving circuit for simultaneously detecting current and voltage signals including the data in the transmission line and applying these signals to a common output impedance, so that an output voltage signal developed across the output impedance will have a sufficient signal level irrespective of the value of other load impedances on the transmission line.

Receiving circuit for a data transmission system

A centralized monitor system can be automatically controlled so that the signal receiving levels in each component of the system can be held at an optimum position even in the presence of noise components, since they are totally free from any failure caused by the noise interference. More particularly, the monitor panel as part of the centralized monitor system collects and displays any alarm information detected by any of the sub units constituting part of the system while using the indoor power line as the data transmission path, enabling the centralized monitor system to generate an alarm upon receipt of such alarm information from the monitor panel, while the automatic receiver gain controller, in responding to an answer back instruction periodically output by the monitor panel, properly controls both the monitor panel and sub units so that both will remain in such positions where their incoming signal levels can be held optimum even under presence of a variety of noise components.

Automatic receiver gain control in centralized monitor system

A system transmits and receives control signals for various types of indoor devices using the existing power wiring in houses and buildings. The transmitter section of the power wiring transmission system is provided with a circuit in which the output of a sine wave oscillator is fed to an emitter-follower through a photocoupler and this output is then fed to the indoor power distribution line through a series resonance circuit after stepping down with a transformer; and the receiving section is provided with a circuit in which the signal from the distribution line is fed to a parallel resonance circuit after passing through a series resonance circuit. Moreover, the input and output sections are resistor terminated.

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Tenri, Japan

Toshiyuki Matsubara