Abstract: A communication system containing a constellation encoder, a feedback precoder, and an interleaver that is coupled to the feedback precoder, enables efficient trellis encoding by preventing adjacent transmit symbols from having the same trellis symbol. Consequently, the adverse impact of quantization noise that may occur over adjacent transmitted symbols is minimized. The constellation encoder uses redundant bits that are generated by a trellis encoder connected to the interleaver, the redundant bits being added to an input stream of data bits being provided to the communication system for transmission. The trellis encoder generates the redundant bits based on the interleaved storage of trellis symbols bits in the interleaver.

Abstract: The present invention provides methods and apparatus for transmitting a data-bearing signal and a non-data-bearing signal. One embodiment comprises communicatively coupling a data-bearing signal during a first time period and communicatively coupling a non-data-bearing signal during a second time period. The data-bearing signal has a first PSD. The non-data-bearing signal has a second PSD substantially the same as the first over a range of frequencies. The non-data-bearing signal has characteristics facilitating echo cancellation. Another embodiment comprises a line interface and a transmitter coupled to the line interface, comprising a data encoder and a periodic signal generator. The encoder is configured to produce a data-bearing signal with a first PSD. The periodic signal generator is configured to produce a non-data-bearing signal with a second PSD. The second PSD is substantially the same as the first PSD over a first range of frequencies.

Abstract: Indirect digital subscriber line (DSL) service generally involves connecting conversion equipment that converts between DSL service delivered to a customer premises and DSL service that connects back to a data network. Indirect DSL service may be delivered on the same loop to the customer premises that also carries a native 0-4 KHz POTS interface. For larger deployments, the conversion equipment may include inverse multiplexing to combine multiple links back to the data network to support DSL service. Furthermore, the conversion equipment may include functions to digitize the POTS service. Aggregating DSL data from multiple customers and/or digitizing POTS service that may be multiplexed with the DSL data allows for significant pair gain opportunities.

Abstract: A digital subscriber line (DSL) communication device employs a linear block interleaver for mathematically combining multiple symbols from a signaling constellation into n-symbol combinations in order to efficiently suppress or eliminate impulse noise generated in the communication channel. In architecture the linear block interleaver includes logic configured to combine multiple symbols from a signaling constellation into n-symbol combinations. The multiple symbols are mathematically combined such that noise energy present in at least one of the n-symbol combinations is spread among each of the multiple symbols, thus reducing the energy of the noise on each of the multiple symbols.

Abstract: The preferred embodiments of the present invention generally provide improved communications over a subscriber loop that is loaded with at least one and potentially a plurality of load coils. The preferred embodiments of the present invention will work over loaded subscriber loops that also support a native POTS interface as well as over loaded subscriber loops that are not providing a native POTS interface. Furthermore, although the preferred embodiments of the present invention are intended to address the technical and business problems of service providers delivering digital subscriber line service over loaded loops, the preferred embodiments will also work over unloaded loops.

Abstract: Systems and methods for encoding fractional bit rates in a pulse amplitude modulation (PAM) communication system are provided. The systems and methods enable a first PAM transceiver to specify to second PAM transceiver a desired fractional bit rate for transmitting data to the first PAM transceiver. In this manner, the systems and methods of the present invention for the first time enable a single standardized specification of a generalized transmitter that may be used to implement any type of fractional encoding or mapping.

Abstract: An ebonite preform is made either of a single component mixture or a two-component mixture. A single component mixture includes unsaturated polymers, a sulfur vulcanization agent, a sulfur solubilizer, a vulcanization accelerator, and a vulcanization activator. Preferably, the sulfur solubilizer is polyamine, and the vulcanization accelerator is tetramethylthiuram disulfide. Reaction of polyamine and tetramethylthiuram disulfide causes a gelation in the mixture at ambient condition. A two-component mixture includes first and second components. First component includes first unsaturated polymers having first functional groups capable of reaction at ambient temperature, a sulfur vulcanization agent, and a vulcanization activator. Second component includes second unsaturated polymers having second functional groups that will react with first functional groups of the first unsaturated polymers at ambient condition, which causes a gelation in the mixture.

Abstract: A system and method for the transmission of additional special marker symbols in a signal space constellation allows the communication of additional control information with minimal additional power to transmit the additional symbol. Additional symbols can include “Start of Message”, “End of File”, “End of Transmission”, “Increase Data Rate”, “Decrease Data Rate”, “Save State” or “Clear”, or any additional command signal desired to be transmitted.

Abstract: An ebonite tape for coating metal substrates is made either of a single component mixture or a two-component mixture. A single component mixture includes unsaturated polymers, a sulfur vulcanization agent, a sulfur solubilizer, a vulcanization accelerator, and a vulcanization activator. Preferably, the sulfur solubilizer is polyamine, and the vulcanization accelerator is tetramethylthiuram disulfide. Reaction of polyamine and tetramethylthiuram disulfide causes a gelation in the mixture at ambient condition. A two-component mixture includes first and second components. First component includes first unsaturated polymers having first functional groups capable of reaction at ambient temperature, a sulfur vulcanization agent, and a vulcanization activator. Second component includes second unsaturated polymers having second functional groups that will react with first functional groups of the first unsaturated polymers at ambient condition, which causes a gelation in the mixture.

Abstract: A liquid ebonite mixture for coating includes two reactive components. The first component contains first unsaturated polymers having first functional groups capable of reaction at ambient condition either with or without a catalyst, a vulcanization agent, and a vulcanization activator. The second component contains second unsaturated polymers having second functional groups that will react with the first functional groups at ambient temperature. The first and the second unsaturated polymers must contain sufficient unsaturated backbones to allow vulcanization with the vulcanization agent. In addition, the second unsaturated polymers must be thermodynamically compatible with the first unsaturated polymers so that macroscopic phase separation will not occur and the vulcanization can happen homogeneously through out the coating.

Abstract: The present invention provides a method and apparatus for performing a multipoint polling protocol which employs silence intervals for controlling operation of the multipoint circuit. When a tributary station which has no data to send is polled by a control device, the tributary station does not send any signal in response to the poll. The control device measures the time which has lapsed since the last poll was sent and compares it to a “no-data” silent threshold timing interval. When the elapsed silent time exceeds the threshold interval, the control device assumes that the tributary has no data to send and immediately sends the next message. If the beginning of a non-silent response is detected before the threshold interval has passed, the control device receives the response and processes the response in the normal manner, e.g., in the manner in which typical multipoint polling protocols process responses.

Abstract: Several embodiments of an interleaved generalized convolutional encoder system and method are provided for communicating data over a transmission path in order to inhibit distortion caused by impulse noise or other correlated noise and enhance transmission rate of data communications. The encoder system is designed to introduce a variable delay to the convolutional encoder. The variable delay effectively spreads correlated noise over a variable number of symbols in time. Correlated noise that is spread over time allows for better error correction encoding.

Abstract: A system and method for shaping a transmit signal spectrum allows a transmit precoder and a spectral shaping filter to precode and shape a transmit signal without the need for receiving communication channel response information from a receiver or the need for a training period. The resultant shaped transmit spectrum signal meets regulatory requirements for the amount of energy transmitted per hertz of bandwidth.

Abstract: A discrete multitone interleaver system, including an interleaver and deinterleaver, are provided for efficiently communicating data despite noise affecting a Discrete Multitone modulation (DMT) system. The discrete multitone interleaver includes a convolutional encoder capable of receiving a plurality of bits on tones and capable of outputting a convolutionally encoded plurality of bits and a synchronized dual skipping switch capable of passing the plurality of bits on tones to the convolutional encoder in a non-sequential order and capable of outputting the convolutionally encoded plurality of bits in the same non-sequential order.

Abstract: A tone ordered discrete multitone interleaver system and method, including a tone ordered interleaver and deinterleaver, are provided for efficiently communicating data despite noise affecting a Discrete Multitone modulation (DMT) system. The tone ordered discrete multitone interleaver forces interleaving of trellis encoded information by assigning a different number of bits to adjacent tones or adjacent tone pairs.

Abstract: An improvement to a half duplex multipoint communication environment wherein a pilot tone enables a control modem to maintain synchronization with a plurality of remote modems. By employing a VCXO in a remote modem, a low jitter timing pulse is generated thus allowing a control modem to maintain synchronization with a plurality of remote modems.

Abstract: In a communications environment where it is desirable to allow the simultaneous transmission of digital data and conventional voice on a single communication line, an audio distortion canceler method and apparatus is configured to adaptively cancel the nonlinear low frequency audible harmonic distortion caused by a device, such as a conventional telephone, connected to the communication line. The method and apparatus of the present invention has application where a harmonic distortion signal resides in a region of the frequency spectrum that is apart from that of the transmit spectrum.

Abstract: A system and method for the transmission of additional special marker symbols in a circular signal space constellation allows the communication of additional control information without requiring any additional power to transmit the additional symbol. Additional symbols can include "Start of Message", "End of File", "End of Transmission", "Increase Data Rate", "Decrease Data Rate", "Save State" or "Clear", or any additional command signal desired to be transmitted.

Abstract: An improvement to a half duplex multipoint communication environment wherein a pilot tone enables a control device to maintain synchronization with a plurality of remote devices. The present invention employs a quantization noise compensator apparatus and method to supply a single bit, two level analog signal to drive a Voltage Controlled Crystal Oscillator (VCXO) in a remote device. The VCXO derives the sample rate signal for both transmit and receive devices, eliminating the requirement for a highly accurate digital to analog converter, thus reducing the cost and complexity of the system while allowing continuous synchronization between a control device and a plurality of remote devices.

Abstract: A system and method for optimizing the uncoded transmission and reception, or modulation and demodulation, of data using circular constellations by using circular preceding and nonlinear encoding. This system allows increased data rate by improving channel efficiency and signal-to-noise ratio.