Methods, and apparatus, for transmitting high-bit-rate digital data in power line communication media having high harmonic noise content
First Claim
1. A method for transmitting binary data, comprising the steps of:
- (a) providing a variable-frequency transmitter having a predetermined center frequency;
(b) selecting a bit time interval in which a bit of said binary data is to be transmitted;
(c) causing the transmitter instantaneous frequency to be at the center frequency at the beginning and end of each bit time interval;
(d) continuously varying without discontinuity the instantaneous transmitting frequency at least once during a bit time interval to a maximum frequency greater than the center frequency and then to a minimum frequency less than the center frequency, with the maximum frequency and the minimum frequency respectively occurring at one-quarter and three-quarters of the bit time interval, to transmit a first binary condition; and
(e) continuously varying without discontinuity the instantaneous transmitter frequency at least once during a bit time interval to a minimum frequency less than the center frequency and then to a maximum frequency greater than the center frequency, with the minimum frequency and maximum frequency respectively occurring at one-quarter and three-quarters of the bit time interval, to transmit a second binary condition.
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Abstract
In a power line data communications system, high-bit-rate digital data is transmitted through a communications media, having high harmonic noise content, by use of a frequency-modulated chirp waveform. The chirp waveform instantaneous frequency is at a predetermined center frequency at the start, midpoint and end of each bit time interval, and makes substantially linear frequency changes to a maximum frequency and a minimum frequency at selected ones of the one-quarter and three-quarter bit-time-interval times. A binary-one data bit is transmitted by increasing the instantaneous frequency to reach the maximum frequency at the one-quarter interval time, then decreasing the frequency to reach a minimum frequency at the three-quarter interval time, and reducing the instantaneous frequency thereafter to reach the center frequency at the end of the bit time interval. A binary-zero data bit is transmitted by initially decreasing the instantaneous frequency to reach the minimum frequency at the one-quarter interval time, then increasing the instantaneous frequency to reach the maximum frequency at the three-quarter interval time, and reducing the instantaneous frequency thereafter to reach the center frequency at the end of the bit time interval.
One presently preferred embodiment of apparatus for transmitting the chirp frequency-modulation signal, and one presently preferred embodiment of apparatus for receiving the chirp frequency-modulated waveform for recovering the data modulated thereon, and associate timing information, are disclosed.
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Citations
39 Claims
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1. A method for transmitting binary data, comprising the steps of:
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(a) providing a variable-frequency transmitter having a predetermined center frequency; (b) selecting a bit time interval in which a bit of said binary data is to be transmitted; (c) causing the transmitter instantaneous frequency to be at the center frequency at the beginning and end of each bit time interval; (d) continuously varying without discontinuity the instantaneous transmitting frequency at least once during a bit time interval to a maximum frequency greater than the center frequency and then to a minimum frequency less than the center frequency, with the maximum frequency and the minimum frequency respectively occurring at one-quarter and three-quarters of the bit time interval, to transmit a first binary condition; and (e) continuously varying without discontinuity the instantaneous transmitter frequency at least once during a bit time interval to a minimum frequency less than the center frequency and then to a maximum frequency greater than the center frequency, with the minimum frequency and maximum frequency respectively occurring at one-quarter and three-quarters of the bit time interval, to transmit a second binary condition. - View Dependent Claims (2, 3, 4)
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5. A method for communicating binary data over a communications medium, comprising the steps of:
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(I) transmitting binary data by; (a) defining a bit time interval during which a single bit of data is to be communicated; (b) converting each data bit to a first signal waveform having a first binary condition in the first and fourth quarters of the bit time interval and having the remaining binary condition in the second and third quarters of the bit time interval; (c) integrating the first signal waveform to obtain a triple-ramp waveform; (d) providing a transmitter having an output waveform of variable instantaneous frequency controlled by the instantaneous magnitude of an input waveform at a transmitter control input; (e) setting the transmitter to have a predetermined center frequency with a predetermined input waveform magnitude at the control input; and (f) applying the triple-ramp waveform as the input waveform to the transmitter control input to vary the instantaneous frequency of the transmitter output to have the center frequency at the beginning, midpoint and end of each bit time interval and to have a maximum frequency, greater than the center frequency, and then a minimum frequency, less than the center frequency, to transmit a data bit having a first binary data value and to have the minimum frequency and then the maximum frequency to transmit a data bit having a second binary data value; (II) conveying the transmitter output waveform over the medium to at least one receiver; and (III) recovering the binary data contained in the transmitter output waveform received signal at each of the at least one receiver by; (a) frequency-demodulating the frequency variations of the received signal; (b) integrating the frequency-demodulated signal; and (c) comparing the integrated and frequency-demodulated signal with a reference level to obtain the binary value of each data bit sent by the transmitter. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 22, 23, 24, 25, 26, 27)
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19. Apparatus for transmitting a chirp frequency-modulated carrier responsive to the binary value of a data bit occurring in a bit time interval, comprising:
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means receiving each binary data bit for providing a triple-ramp waveform having a predetermined value at at least the beginning and end of each bit time interval and having a maximum value, greater than the predetermined value, preceding a minimum value, less than the predetermined value, if a first binary condition is to be transmitted and having the minimum value preceeding the maximum value if a second binary condition is to be transmitted; and means having a control input receiving the triple-ramp waveform for providing a carrier waveform at a predetermined center frequency responsive to receipt of said predetermined value at the control input and having an instantaneous frequency differing from said center frequency responsive to the instantaneous value of the triple-ramp waveform. - View Dependent Claims (20, 21)
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28. Apparatus for recovering the binary value during a bit time interval of a data bit transmitted as a chirp-frequency-modulated carrier signal, comprising:
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input means for receiving the chirp-frequency-modulated signal; means for frequency demodulating the chirp-frequency-modulated signal at said input means to provide an output signal having a magnitude responsive to the instantaneous frequency of the received chirp-frequency-modulated signal; means for integrating, with respect to time, the output signal of the frequency demodulating means; and means for comparing the integrating means output with a reference level to obtain the binary value of the data bit encoded on the chirp-frequency-modulated carrier signal received at said input means during each bit time interval. - View Dependent Claims (29, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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30. Apparatus for recovering the binary value during a bit time interval of a data bit transmitted as a chirp-frequency-modulated carrier signal, comprising:
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input means for receiving the chirp-frequency-modulated signal; means for frequency demodulating the signal at said input means and providing an output signal having a magnitude responsive to the instantaneous frequency of the received signal; means for integrating, with respect to time, the output signal of the demodulating means; means for comparing the integrating means output with a reference level to obtain the binary value of the data bit encoded on the chirp-frequency-modulated carrier signal received at said input means during each bit time interval; and means for recovering a data clock waveform from the integrating means output and including;
means for full-wave rectifying the integrating means output;
means for providing a threshold level; and
means for comparing the rectifying means output with the threshold level to recover a clock waveform having a single pulse during each bit time interval.
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Specification