Communication system with multicarrier telephony transport
First Claim
1. A multicarrier transmitting modem for a communications system, comprising:
- a port for receiving multiple serial strings of digital data;
a scrambler for randomizing the strings of digital data, wherein the scrambler randomizes different ones of the multiple strings differently by varying the polynomials and seeds of the scrambler;
a mapper for converting the randomized strings into randomized digital symbols representing the strings of digital data;
an inverse discrete FFT transformer for converting the randomized symbols into digital representations of multiple modulated orthogonal carriers;
means for converting the digital representations into an analog waveform; and
an amplifier for transmitting the analog waveform to the communications system.
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Accused Products
Abstract
A communication system for transferring digital data over a distribution network is described. The communication system includes an interface for receiving successive strings of digital data from a source, each string representing a certain number of bits. The system also includes a symbol mapper for converting the strings into a sequence of symbols representing a constellation of discrete values of the amplitude and phase of a carrier for a predetermined period. The constellation is rotationally asymmetric for valid ones of the data strings. The system further includes a modulator for synthesizing a plurality of orthogonal carriers from said symbols a transmitter for sending the modulated carriers over a distribution network.
124 Citations
5 Claims
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1. A multicarrier transmitting modem for a communications system, comprising:
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a port for receiving multiple serial strings of digital data;
a scrambler for randomizing the strings of digital data, wherein the scrambler randomizes different ones of the multiple strings differently by varying the polynomials and seeds of the scrambler;
a mapper for converting the randomized strings into randomized digital symbols representing the strings of digital data;
an inverse discrete FFT transformer for converting the randomized symbols into digital representations of multiple modulated orthogonal carriers;
means for converting the digital representations into an analog waveform; and
an amplifier for transmitting the analog waveform to the communications system. - View Dependent Claims (2, 3)
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4. A multicarrier transmitting modem, comprising:
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a serial port that receives multiple serial strings of digital data;
a scrambler coupled to the serial port that randomizes the strings of digital data, wherein the scrambler comprises a first and a second scrambler, wherein the first scrambler has different polynomial and seed patterns from the second scrambler;
a symbol mapping device coupled to the scrambler that converts the randomized strings into randomized digital symbols representing the strings of digital data;
an inverse discrete FFT transformer coupled to the symbol mapping device that converts the randomized symbols into digital representations of multiple modulated orthogonal carriers;
a digital to analog converter coupled to the inverse discrete FFT transformer;
a reconstruction filter coupled to the digital to analog converter; and
an amplifier coupled to the reconstruction filter. - View Dependent Claims (5)
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Specification