Abstract: Systems and methods for orthogonal frequency division multiplexing are provided.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising a plurality of spectrally overlapping carrier signals from at least two of a plurality of remote units, wherein the plurality of spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission to the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to instruct the transmitter to transmit a predetermined identifier on at least one of the spectrally overlapping carrier signals, the predetermined identifier identifying to a first remote unit a range of the plurality of spectrally overlapping carrier signals for the first remote unit to receive control information.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising a plurality of spectrally overlapping carrier signals from at least two of a plurality of remote units, wherein the plurality of spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission to the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; and a controller programmed to analyze a training signal received from a first remote unit and adjust receiver equalizer parameters based on the training signal.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising a plurality of spectrally overlapping carrier signals from at least two of a plurality of remotes, the carrier signals are modulated using an inverse Fourier transform; a transmitter; a processor coupled to the transmitter, the processor outputs data for transmission to the transmitter, the processor applies an inverse Fourier transform to the data provided to the transmitter; a controller programmed to instruct the transmitter to transmit timing adjustments to the at least two of the plurality of remotes, the timing adjustments instruct the at least two of the plurality of remotes to adjust transmission timing so that transmitted symbols associated with frames of a predetermined multiframe structure are received in sequence from the at least two of the plurality of remotes based on the structure.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises:a receiver configured to de-modulate symbols from at least one of a plurality of spectrally overlapping carrier signals; a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter; the processor programmed to encode upstream information using a forward error correction algorithm based on forward error correction parameters received by the receiver.

Abstract: A distortion monitor for a non-linear device is provided. The control circuit includes an input coupleable to receive a signal from the non-linear device and a first frequency monitor coupled to the input. The frequency monitor monitors the level of one of even and odd order distortion at a first frequency and creates a first signal indicative of the level of the distortion without the use of a pilot tone.

Abstract: A method of decoding a signal in an optical fiber. In one embodiment the method includes receiving the optical signal, wherein the optical signal is a pulse amplitude modulated signal. Converting the optical signal to an electrical signal. Comparing the electrical signal with a plurality of levels. Producing comparison output signals based on the comparison of the electrical signal with the plurality of levels. Processing the comparison output signals on a clock to produce processed output signals and latching the processed output signals on a clock signal to generate the plurality of serial, digital data streams.

Abstract: A transmitter that performs stimulated Brillouin scattering suppression is provided. The transmitter includes a non-linear device having an optical input adapted to receive an optical signal, an amplitude modulation input adapted to receive an amplitude modulation signal, a phase modulation input and an output. The transmitter also includes a stimulated Brillouin scattering (SBS) oscillator/driver having first and second oscillators coupled to the phase modulation input of the non-linear device and an amplifier coupled to the output of the non-linear device. The transmitter further includes a laser coupled to the optical input of the non-linear device.

Abstract: A distortion monitor for a non-linear device is provided. The control circuit includes an input coupleable to receive a signal from the non-linear device and a first frequency monitor coupled to the input. The frequency monitor monitors the level of one of even and odd order distortion at a first frequency and creates a first signal indicative of the level of the distortion without the use of a pilot tone.

Abstract: A semiconductor laser diode for transmitting optical signals in a telecommunications network is housed within a module supported adjacent to a thermoelectric cooling element that is mounted in thermally conductive contact with a heat sink. The cooling element is positioned externally on the surface of the module. The adjacent surface areas of the module and the cooling element are brought into thermal conductivity by a thermally conductive filler occupying the space between the module and the cooling element. The filler conforms to the configuration of the adjacent surfaces of the module and the cooling element to increase the thermal conductivity therebetween for maximum efficiency in the transfer of heat from the laser diode through the module to the cooling element and the heat sink.

Abstract: A distortion monitor for a non-linear device is provided. The control circuit includes an input coupleable to receive a signal from the non-linear device and a first frequency monitor coupled to the input. The frequency monitor monitors the level of one of even and odd order distortion at a first frequency and creates a first signal indicative of the level of the distortion without the use of a pilot tone.

Abstract: An analog to digital conversion circuit is provided. The analog to digital (A/D) conversion circuit includes an input adapted to receive an analog signal. The A/D conversion circuit further includes a variable attenuator that is coupled to the input and that has a feedback control input. The A/D conversion circuit further includes a converter that is responsive to the variable attenuator and that converts analog input signals to digital output signals. A feedback loop is also provided. The feedback loop is responsive to an overflow indicator of the converter. The feedback loop is adapted to produce a feedback signal based on the overflow indicator and is adapted to provide the feedback signal to the feedback control input of the variable attenuator so as to maintain the peak level of the input to the converter substantially near an acceptable peak input level for the converter.

Abstract: An optical communication system is provided. The optical communication system includes an optical fiber, an optical transmitter, and an optical receiver. The optical transmitter is coupled to the optical fiber. The optical transmitter is adapted to encode a pulse amplitude modulated optical signal based on at least two, independent input signals. The optical receiver is coupled to the optical fiber. The optical receiver is adapted to decode the pulse amplitude modulated optical signal to reproduce the at least two, independent input signals as output signals.

Abstract: An optical communication system is provided. The optical communication system includes an optical fiber, an optical transmitter, and an optical receiver. The optical transmitter is coupled to the optical fiber. The optical transmitter is adapted to encode a pulse amplitude modulated optical signal based on at least two, independent input signals. The optical receiver is coupled to the optical fiber. The optical receiver is adapted to decode the pulse amplitude modulated optical signal to reproduce the at least two, independent input signals as output signals.

Abstract: A method for controlling a plurality of service units in a telecommunications system with a multi-carrier transmission scheme is provided. Specifically, in one embodiment, the method includes broadcasting control signals for the service units over a plurality of control channels distributed in a number of subbands of a frequency bandwidth. The method further includes identifying the service unit to use the control signal with an identifier.

Abstract: A apparatus for providing a Fast Fourier Transform (FFT) and an inverse FFT is provided. The apparatus comprises a radix-N core. The radix-N core includes at least N multipliers. The radix-N core also includes a twiddle-factor lookup table that stores complex twiddle-factors. The twiddle-factor lookup table is coupled to one input of each of the multipliers. The radix-N core also includes a conversion random access memory (RAM) that stores transform points. The conversion RAM is coupled to another input of each of the multipliers. The radix-N core also includes an array of at least N-times-N adder-subtracter-accumulators.

Abstract: A multicarrier transmitting modem is described.

Abstract: A method of computer data transmission over a telecommunications network having a head end connected to a plurality of service units is provided. The method includes receiving a request for transmitting computer data over the network from a service unit, retrieving provisioning information for the service unit, and selectively assigning one or more data channels based on the provisioning information to transmit the computer data over the network to provide a data path with substantially constant data transfer bandwidth between a head end and the service unit.

Abstract: A video and telephony signal distribution network is provided. The network includes a head end for transmitting to a plurality of remote units. The network further includes at least one optical/electrical converter unit that transmits to the remote units over at least two coaxial cables coupled to a common optical/electrical converter unit. Each remote unit transmits upstream electrical data signals over its associated coaxial cable to the optical/electrical converter unit using a common bandwidth. The optical/electrical converter unit converts and frequency shifts the upstream electrical data signals from at least one remote unit to form an optical upstream data signal for transmittal to the head end such that the frequency spectrum used for the upstream communications is simultaneously used on each of the coaxial cables of to optical/electrical converter unit.