Power line communication while avoiding determinable interference harmonics
First Claim
1. A power line communication (PLC) apparatus comprising:
- an input buffer for accepting input data from a data source;
a modulation circuit, coupled to said input buffer, for generating a carrier signal at a predetermined frequency, said predetermined frequency being between interference harmonics, said modulation circuit further including a circuit for modulating said input data at a predetermined symbol duration with said carrier signal, said modulation circuit further including a waveshaping memory for storing a digital representation of said carrier signal, said predetermined carrier signal frequency and said predetermined symbol duration being arbitrarily selectable based on the digital information stored in said waveshaping memory;
a transmitter, coupled to said modulation circuit, for transmitting said modulated input data on a power line, said modulated data being transmitted between said interference harmonics;
a receiver for receiving said modulated data on said power line; and
a filter means, coupled to said receiver, for filtering said modulated data to reject said interference harmonics while accepting said input data.
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Accused Products
Abstract
A power line communication (PLC) apparatus wherein a carrier is derived to avoid determinable interference harmonics. In order to transmit data on a power line containing the television interference or other determinable interference harmonics, the present invention uses redundant carriers at a frequency between the television interference harmonics. In the preferred embodiment, the first carrier is positioned at 118 KHz and the redundant carrier is positioned at 133.7 KHz for the PLC apparatus designed for use in the United States. Other carrier frequencies are used for other countries in order to avoid interference harmonics at a slightly different frequency. The present invention includes a waveshaping and modulation circuit for generating the modulated data waveform for output over the power line. In the preferred embodiment, the waveshaping and modulation circuit includes a waveshape ROM for storing samples that represent the appearance of the carrier waveshape. Once the appropriate waveshape is selected from the waveshape ROM, the 256 discrete points of the waveshape are clocked out an interface line to a DAC, a filter, an amplifier and on to a PLC coupling network for isolating and coupling the signal onto the power line. On the receive side, receive filters are used to separate the received data from determinable interference harmonics. These filters comprise four matched filters, two for each channel. These filters operate in cooperation with the waveshaping and modulation circuitry in order to capture the signals modulated between determinable interference harmonics such as television interference harmonics.
204 Citations
10 Claims
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1. A power line communication (PLC) apparatus comprising:
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an input buffer for accepting input data from a data source; a modulation circuit, coupled to said input buffer, for generating a carrier signal at a predetermined frequency, said predetermined frequency being between interference harmonics, said modulation circuit further including a circuit for modulating said input data at a predetermined symbol duration with said carrier signal, said modulation circuit further including a waveshaping memory for storing a digital representation of said carrier signal, said predetermined carrier signal frequency and said predetermined symbol duration being arbitrarily selectable based on the digital information stored in said waveshaping memory; a transmitter, coupled to said modulation circuit, for transmitting said modulated input data on a power line, said modulated data being transmitted between said interference harmonics; a receiver for receiving said modulated data on said power line; and a filter means, coupled to said receiver, for filtering said modulated data to reject said interference harmonics while accepting said input data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification
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- Resources
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Current AssigneeEchelon Corporation (Renesas Electronics Corporation)
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Original AssigneeEchelon Corporation (Renesas Electronics Corporation)
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InventorsLee, Chin-Chen, Johnson, Howard W., Sutterlin, Philip H.
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Primary Examiner(s)Peng, John K.
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Assistant Examiner(s)TONG, NINA C
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Application NumberUS08/167,431Time in Patent Office477 DaysField of Search340/310 R, 340/310 A, 340/310 CP, 375/39, 375/37, 375/51, 375/57, 375/58, 375/60, 358/167, 455/3.3, 455/63, 455/114US Class Current375/261CPC Class CodesH04B 2203/5416 by adding signals to the wa...H04B 2203/5425 improving S/N by matching i...H04B 2203/5445 Local networkH04B 2203/545 Audio/video application, e....H04B 2203/5483 using coupling circuitsH04B 2203/5491 using filtering and bypassingH04B 3/542 the information being in di...H04L 27/18 Phase-modulated carrier sys...
