An optical network is disclosed which includes an optical fiber shared by a plurality of transmitters using code division multiple access techniques. The transmitters are connected by tributary optical fibers to the shared optical fiber. In code division multiple access techniques, each communication is encoded with a distinctive code which enables a receiver to extract the communication intended for it from amongst communications intended for other receivers. It is found that synchronizing the communications on the optical fiber improves the ability of a receiver to extract the communication intended for it. Injecting an optical pulse signal into the optical network, and using the tributary optical fibers to carry the clock signal to the transmitters provides an inexpensive method of synchronizing the transmitters which feed signals onto the optical fiber. The technology is of use in optical networks, and other transmission line networks, and is well-suited to use in local area networks.

In accordance with some embodiments, a system includes a line locator and a device configured to communicate through an internet with a server also coupled to the internet. Furthermore, a plurality of line locate transmitters are distributed geographically and configured to communicate through the internet with the server. The server operates to activate one of the plurality of line locate transmitters based on a geographic location of the device.

In accordance with some embodiments, a system includes a line locator and a device configured to communicate through an internet with a server also coupled to the internet. Furthermore, a plurality of line locate transmitters are distributed geographically and configured to communicate through the internet with the server. The server operates to activate one of the plurality of line locate transmitters based on a geographic location of the device.

A method of reducing transmission power for an encoded data stream includes the steps of receiving an incoming data stream having equal probability for a plurality of incoming data bits, assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits, and transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols.

A method of reducing transmission power for an encoded data stream includes the steps of receiving an incoming data stream having equal probability for a plurality of incoming data bits, assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits, and transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols.

A logging tool is positioned downhole in a wellbore, where the logging tool communicates with a computer on the Earth's surface over an analog signal path. Tool data is received from a sensor associated with the logging tool and encoded into a symbol signal. The symbol signal is transmitted to a receiver system via the analog signal path. The receiver system has one or more filters to filter the symbol signal. The one or more filters includes an equalizer filter indicative of an analog signal path response of the analog signal path. The filtered symbol signal is decoded into second tool data. The second tool data is encoded into second symbols and based on the second symbols, an updated analog signal path response of the analog signal path is generated to update the equalizer filter.

A logging tool is positioned downhole in a wellbore, where the logging tool communicates with a computer on the Earth's surface over an analog signal path. Tool data is received from a sensor associated with the logging tool and encoded into a symbol signal. The symbol signal is transmitted to a receiver system via the analog signal path. The receiver system has one or more filters to filter the symbol signal. The one or more filters includes an equalizer filter indicative of an analog signal path response of the analog signal path. The filtered symbol signal is decoded into second tool data. The second tool data is encoded into second symbols and based on the second symbols, an updated analog signal path response of the analog signal path is generated to update the equalizer filter.

A wired communication system includes a bidirectional channel for sending information in one direction at a high bandwidth and sending control information for configuring a transmitter in the other direction at a lower bandwidth. Embodiments of the disclosure may use a primary transmitter output stage in the transmitter and a primary receiver input stage in the receiver to send and receive data or a clock, for example. An auxiliary transmitter output stage in the receiver and auxiliary receiver input stage in the transmitter send and receive control information for configuring the transmitter to efficiently send data over a wired channel.

A wired communication system includes a bidirectional channel for sending information in one direction at a high bandwidth and sending control information for configuring a transmitter in the other direction at a lower bandwidth. Embodiments of the disclosure may use a primary transmitter output stage in the transmitter and a primary receiver input stage in the receiver to send and receive data or a clock, for example. An auxiliary transmitter output stage in the receiver and auxiliary receiver input stage in the transmitter send and receive control information for configuring the transmitter to efficiently send data over a wired channel.

Methods and systems capable of launching signal-carrying transverse electromagnetic waves onto a transmission line in the higher voltage region of the transmission distribution network. Such methods and systems may include a surface wave launcher located in the higher voltage region, a network unit located in a lower voltage region, and an arrester separating the surface wave launcher and the network unit, the arrester preventing voltage from arcing over from the higher voltage region to the lower voltage region where the arrester provides the signal to the surface wave launcher.