An input/output (I/O) and control system for long distance communications and industrial applications having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave of configurable frequency on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. Changing the synchronization pulse length increases bandwidth for shorter, less noisy and more stable systems and inversely decreases bandwidth for increased noise immunity and distance for longer, noisier and less stable systems.

An input/output (I/O) and control system for long distance communications and industrial applications having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave of configurable frequency on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. Changing the synchronization pulse length increases bandwidth for shorter, less noisy and more stable systems and inversely decreases bandwidth for increased noise immunity and distance for longer, noisier and less stable systems.

Embodiments of the present invention provide a nonlinear precoding bit loading method, a transmit end, a receive end, and a system. The method includes: determining, power control factors of multiple preset quantities of bits; obtaining, a first correspondence between the multiple preset quantities of bits and signal to noise ratios without power control; determining, a second correspondence between the multiple preset quantities of bits and signal to noise ratios with power control according to the power control factors and the first correspondence; and after actually measuring a signal to noise ratio with power control on a subcarrier, determining, according to the second correspondence, a preset quantity of bits corresponding to the actually measured signal to noise ratio with power control, using the determined preset quantity of bits as an actual bit loading quantity of the subcarrier, and notifying a transmit end of the actual bit loading quantity.

Embodiments of the present invention provide a nonlinear precoding bit loading method, a transmit end, a receive end, and a system. The method includes: determining, power control factors of multiple preset quantities of bits; obtaining, a first correspondence between the multiple preset quantities of bits and signal to noise ratios without power control; determining, a second correspondence between the multiple preset quantities of bits and signal to noise ratios with power control according to the power control factors and the first correspondence; and after actually measuring a signal to noise ratio with power control on a subcarrier, determining, according to the second correspondence, a preset quantity of bits corresponding to the actually measured signal to noise ratio with power control, using the determined preset quantity of bits as an actual bit loading quantity of the subcarrier, and notifying a transmit end of the actual bit loading quantity.

A signal conditioning device for conditioning bi-directional radiofrequency (RF) signals in a telecommunications network is provided. The signal conditioning device can allow for the conditioning of both upstream and downstream components of a bi-directional telecommunications signal in a telecommunication system using a signal conditioning device disposed at a single location. The signal conditioning device can include first and second line connections and a signal path between the first and second line connections. The signal conditioning device can condition upstream and downstream components of a bi-directional telecommunications signal using plug-in signal conditioning circuits received into one or more external plug-in sockets coupled to the signal path.

A signal conditioning device for conditioning bi-directional radiofrequency (RF) signals in a telecommunications network is provided. The signal conditioning device can allow for the conditioning of both upstream and downstream components of a bi-directional telecommunications signal in a telecommunication system using a signal conditioning device disposed at a single location. The signal conditioning device can include first and second line connections and a signal path between the first and second line connections. The signal conditioning device can condition upstream and downstream components of a bi-directional telecommunications signal using plug-in signal conditioning circuits received into one or more external plug-in sockets coupled to the signal path.

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.

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.

Methods to improve the data carrying capacity of CATV DOCSIS systems and other communications systems are disclosed. Communications channels may be more efficiently spaced with reduced or absent guard bands by using receivers with adaptive signal cancellation methods, equalizing circuits, or polyphase filter banks and Fast Fourier Transform signal processing methods to correct for higher levels of cross-talk. QAM type communications channels may also be utilized on a synchronized two-transmitter at a time basis by adjusting the transmitters to predefined signal levels, such as +1, −1, +½, −½ to enable the combined signals to be distinguished at the receiver. These two methods may be combined to create a still higher data throughput system.

Methods to improve the data carrying capacity of CATV DOCSIS systems and other communications systems are disclosed. Communications channels may be more efficiently spaced with reduced or absent guard bands by using receivers with adaptive signal cancellation methods, equalizing circuits, or polyphase filter banks and Fast Fourier Transform signal processing methods to correct for higher levels of cross-talk. QAM type communications channels may also be utilized on a synchronized two-transmitter at a time basis by adjusting the transmitters to predefined signal levels, such as +1, −1, +½, −½ to enable the combined signals to be distinguished at the receiver. These two methods may be combined to create a still higher data throughput system.