Power line network system and method
First Claim
1. A circuit comprising:
- a line driver configured and arranged to couple data-carrying symbols over a power line, via a waveform, that carries an alternating current signal having a frequency or phase that varies, relative to a frequency or phase of previous cycles of the alternating current signal, the data-carrying symbols corresponding to respective information signals;
a signal-monitoring circuit configured and arranged for monitoring variations in the alternating current signal;
a lookup table configured and arranged to store data entries that define, at least in part, data useful for providing steps of the waveform; and
a logic circuit configured and arranged to access the data entries in the lookup table, in response to the signal-monitoring circuit, and thereby feed the line driver with stepped data that is processed for modulating the alternating current of the power line with the data-carrying symbols, wherein the steps provided by accessing the lookup table are processed to account for the variations in the alternating current signal.
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Accused Products
Abstract
Various aspects of the instant disclosure are directed towards communicating symbols over a power line carrying alternating current, based upon frequency variations in the alternating current. In accordance with some embodiments, a line driver couples data-carrying symbols over the power line, via a waveform. Variations in the alternating current are monitored and used for accessing a lookup table that stores data entries that define data useful for providing steps of the waveform. The accessed data entries are used to drive a line driver with stepped data, and therein modulating alternating current on the power line with the data-carrying symbols at a frequency that is tied to the frequency of the alternating current.
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Citations
27 Claims
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1. A circuit comprising:
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a line driver configured and arranged to couple data-carrying symbols over a power line, via a waveform, that carries an alternating current signal having a frequency or phase that varies, relative to a frequency or phase of previous cycles of the alternating current signal, the data-carrying symbols corresponding to respective information signals; a signal-monitoring circuit configured and arranged for monitoring variations in the alternating current signal; a lookup table configured and arranged to store data entries that define, at least in part, data useful for providing steps of the waveform; and a logic circuit configured and arranged to access the data entries in the lookup table, in response to the signal-monitoring circuit, and thereby feed the line driver with stepped data that is processed for modulating the alternating current of the power line with the data-carrying symbols, wherein the steps provided by accessing the lookup table are processed to account for the variations in the alternating current signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for coupling data-carrying symbols over a power line that carries an alternating current signal having a frequency or phase that varies, relative to a frequency or phase of previous cycles of the alternating current signal, the data-carrying symbols corresponding to respective information signals, the method comprising:
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monitoring variations in the alternating current signal; storing, in a lookup table, data entries that define, at least in part, data useful for providing steps of a waveform; accessing the data entries in the lookup table, in response to the monitored variations in the alternating current signal, and feeding a line driver with stepped data that is processed for modulating the alternating current of the power line with the data-carrying symbols, wherein the steps provided by accessing the lookup table are processed to account for the monitored variations in the alternating current signal; and coupling the data-carrying symbols over a power line, via a waveform corresponding to the stepped data. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method comprising:
in a processing circuit, generating a plurality of interrupts using a frequency synthesizer having a period defined by a time between the plurality of interrupts, the time between the interrupts being set based upon a fixed number of interrupts to be generated during a cycle of alternating current (AC) carried on power lines over which data is to be communicated; for each of a plurality of symbols, providing two tone values as discrete-frequency signals and phase offsets therebetween, based upon data in the symbols; for each of the plurality of interrupts, accessing values for each tone from a lookup table, based upon the tone values and the phase offset, and driving a transceiver based upon the combined accessed values from the lookup table. - View Dependent Claims (26)
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27. A circuit-based apparatus for communicating over power distribution lines carrying alternating current (AC) power, the apparatus comprising
a digital to analog converter (DAC); -
a frequency locked loop (FLL) circuit configured and arranged to generate a target value defining a base period for each interrupt, based upon a frequency of the AC power, the number of interrupts being generated for each cycle of the AC power being constant; a symbol generator circuit configured and arranged to, for each symbol, select two frequencies and a phase based upon a binary pattern being communicated over the power distribution lines, use the selected frequencies and phase to calculate counter tweak values representing an amount added to an accumulator for each transmit interrupt, and calculate a start value for the accumulator for a second tone based upon a phase of the symbol; a data storage circuit that stores a sine table having values representing step values of a sine wave having half a maximum voltage of the DAC; and a synthesizer circuit configured and arranged to, in response to each interrupt generated by the FLL circuit, generate and provide an output signal to the DAC by indexing into the sine table to retrieve two sine values respectively based upon bits in each of two accumulators, the sine values corresponding to first and second tones having a fixed phase relationship, and add the retrieved sine values to generate combined tones, and in response to a new symbol, clear the accumulator for the first tone and set the accumulator for the second tone to the start value provided by the symbol generator, therein setting a sweep of the sine table at an offset that matches the phase difference of the symbols.
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Specification