Method and apparatus for data transmission using chirped frequency-shift-keying modulation
First Claim
1. A method for transmission of digital data, comprising the steps of:
- (a) transmitting a carrier having a selected substantially-constant initial frequency fc ;
(b) providing a sequence of substantially-constant data bit time intervals, each commencing essentially at the termination of the previous data bit time interval, and during each of which one bit of said digital data is to be transmitted;
(c) offsetting the carrier initial frequency, at the start of each data bit transmission time interval, by an offset frequency Δ
f established only by the data value of the data bit to be transmitted in that data bit time interval; and
(d) frequency sweeping the offsetted carrier frequency in a predetermined direction, unrelated to the data value, for the duration of the data bit time interval.
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Accused Products
Abstract
A method for transmission of digital data utilizes a carrier frequency offset in a first frequency direction for a first binary condition, and offset in a second frequency direction for the remaining binary condition, at the start of a bit time interval. The carrier frequency is swept in a preselected frequency direction during each bit time interval, to produce a chirped frequency-shift-keyed waveform in the frequency domain, for transmission of each bit of binary data. Frequency-shift-keyed demodulation is utilized at a receiving end, with the receiver synchronized to the transmitter bit time interval, to recover the transmitted digital data. Apparatus for data transmission using this chirped frequency-shift-keyed modulation waveform is disclosed.
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Citations
54 Claims
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1. A method for transmission of digital data, comprising the steps of:
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(a) transmitting a carrier having a selected substantially-constant initial frequency fc ; (b) providing a sequence of substantially-constant data bit time intervals, each commencing essentially at the termination of the previous data bit time interval, and during each of which one bit of said digital data is to be transmitted; (c) offsetting the carrier initial frequency, at the start of each data bit transmission time interval, by an offset frequency Δ
f established only by the data value of the data bit to be transmitted in that data bit time interval; and(d) frequency sweeping the offsetted carrier frequency in a predetermined direction, unrelated to the data value, for the duration of the data bit time interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 18, 19, 20, 21, 22)
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9. A method for transmission of digital data, comprising the steps of:
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(a) transmitting a carrier of a selected initial frequency fc ; (b) offsetting the carrier frequency to different sides of the initial carrier frequency fc, at the start of a data bit time interval, by an offset frequency Δ
f established by the different data values of the bit of data to be transmitted; and(c) frequency sweeping the offsetted carrier frequency in a predetermined direction for the duration of the data bit time interval. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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23. Apparatus for communicating digital data over a transmission media by chirp frequency-shift-keying modulation, comprising:
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means receiving the digital data to be transmitted for providing a waveform having an initial frequency offset from a substantially-constant carrier center frequency responsive to the digital data value to be transmitted and for changing frequency in a predetermined manner, unrelated to the digital data value, during a data bit time interval; means for coupling the changing frequency waveform to said transmission medium; means coupled to said transmission medium for receiving said changing frequency waveform; and means for demodulating the received changing frequency waveform to recover the transmitted digital data value. - View Dependent Claims (24, 25, 26, 27, 31, 32, 33, 34)
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28. Apparatus for communicating digital data over a transmission medium by chirp frequency-shift-keying modulation, comprising:
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means receiving the digital data to be transmitted for providing a waveform having an initial frequency offset from a carrier center frequency responsive to the digital data value to be transmitted and changing frequency in a predetermined manner during a data bit time interval; means for coupling the changing frequency waveform to said transmission medium; means coupled to said transmission medium for receiving said changing frequency waveform; means for demodulating the received changing frequency waveform to recover the transmitted digital data value; and means for receiving a predetermined signal available on said media and utilizing said media signal to provide a data bit time interval synchronizing signal at said waveform-providing means and at said demodulating means. - View Dependent Claims (29, 30)
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35. Apparatus for communicating digital data over a transmission media by chirp frequency-shift-keying modulation, comprising:
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means receiving the digital data to be transmitted for providing a waveform having an initial frequency offset from a carrier center frequency responsive to the digital data value to be transmitted and changing frequency in a predetermined manner during a data bit time interval; means for coupling the changing frequency waveform to said transmission medium; means coupled to said transmission medium for receiving said changing frequency waveform; and means for demodulating the received changing frequency waveform to recover the transmitted digital data value, and including;
mixer means receiving a swept local oscillator frequency waveform and said received changing frequency waveform to provide an intermediate-frequency waveform; and
intermediate-frequency waveform demodulator means including;
at least one means for providing a substantially D.C. voltage responsive to receipt of each intermediate frequency representing a digital data value;
means for integrating the substantially D.C. voltage from each of the voltage-providing means;
means for resetting each integrating means prior to the start of each data bit time interval;
means for sampling the output of each integrating means at the end of each data bit time interval; and
means for comparing the sampled integrator means outputs for determining the digital data value received.
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36. A system for carrier frequency communication of serial information bits representative of a plurality of logic states, at a carrier frequency substantially greater than the frequency of information bit transmission, comprising:
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transmitting means, adapted for connection to an alternating-current power line transmission medium, comprising; means for modulating a transmission signal of frequency substantially greater than the frequency of information bit transmission, responsive to the logic state of the information bits to be transmitted; means for producing predetermined variations of frequency in said transmission signal during each time interval in which an information bit is transmitted, to cause the variations to extend over a frequency range substantially greater than the frequency of information bit transmission; and means for synchronizing said predetermined frequency variations with the alternating current on the power line; and receiving means adapted for connection to the power line transmission medium, comprising; means for receiving the transmission signal; means for providing local signals related to the predetermined frequency variations of said transmission signals during each bit time interval and synchronized with the alternating current in the power line; and means for utilizing said local signal to recover the serial information bits representative of each of the plurality of logic states. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44)
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45. Transmitting apparatus for high frequency tranmission of serial information bits of a plurality of logic states over alternating-current power lines, comprising:
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first means adapted for coupling to one of said power lines and responsive to alternating current signals on that power line for producing high-frequency transmission signals having, during each bit time interval of the serial information bits, a predetermined frequency variation synchronized to the alternating current signal on that power line, to cause the transmission signal to vary during each bit time interval over a frequency range that is substantially greater than the frequency at which consecutive information bits recur; and second means responsive to the serial information bits to be transmitted for causing the transmission signal to have a unique predetermined frequency pattern for transmitted information bits of each one of the plurality of logic states. - View Dependent Claims (46, 47, 48)
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49. Receiving apparatus for recovering serial information bits, each capable of having any one of a plurality of logic states, encoded on a high-frequency transmission signal transmitted over an alternating current power line, comprising:
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first means adapted for coupling to the power line for receiving a high-frequency transmission signal having predetermined wide variations in frequency, time-synchronized to the alternating current on the power line, during each bit time interval of the serial information bits encoded thereon; second means adapted for coupling to the power line and responsive to alternating current thereon for producing a variable local frequency signal time-synchronized to the power line alternating current and varying in frequency in a uniform predetermined manner during each bit time interval of the information bits encoded on the transmission signal; and demodulating means for mixing the high-frequency transmission signal and the variable local frequency signal for providing an intermediate-frequency signal and for deriving therefrom information bit signals of an amplitude representative of the logic state of each respective one of the information bits. - View Dependent Claims (50, 51, 52, 53, 54)
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Specification