System and method for high speed data transmission
First Claim
1. In a system where data is sent from a sending system to a receiving system over a band limited channel using a transmission waveform comprising a plurality of individual narrowband waveforms, each comprised of a plurality of substantially phase continuous events with a width based on the data word encoded thereby, a method for high speed data transfer between the sending system and the receiving system, comprising the steps of:
- generating a plurality of substantially phase continuous narrowband waveforms, each comprising a plurality of substantially phase continuous events with a width that is dependent on a data word to be transferred by that event and that lies between a minimum and maximum value selected for each of the plurality of narrowband waveforms so that each of said narrowband waveforms occupies a relatively small portion of the bandwidth of the band limited channel;
generating at least one substantially phase continuous pilot tone;
defining an epoch time;
combining said plurality of narrowband waveforms and said at least one pilot tone into a transmit waveform having the epoch time;
transmitting said transmit waveform to the receiving system, wherein a single frame of data is transferred during said epoch time after which a new epoch is begun that transfers an additional frame of data; and
while transmitting said transmit waveform, inserting a makeup time for any of said plurality of narrowband waveforms which fall short of said epoch time after all data words for the current frame of data have been transferred.
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Abstract
Systems and methods for high speed data transfer that are capable of transferring a vast amount of data in very little bandwidth using current technology are disclosed. The systems employ a plurality of substantially phase continuous waveforms comprised of a plurality of events. Each event is preferably formed by either a positive or negative half period sinusoidal signal with a duration that varies between some minimum and maximum value to encode a data word on each event of the waveform. The event width variations are typically small to maintain a small frequency variation for each individual waveform. In order to allow a receiver to detect the very small time differential between different event widths, a pilot tone is also placed in the waveform. In a receiver, this pilot tone is recovered and used to phase lock the receiver clock, which typically operates at much much greater frequency than the pilot tone. This phase locked receiver clock can then be used to time the zero crossings of each event in order to extract the data word encoded into each event of the phase continuous waveforms. The individual substantially phase continuous waveforms are extracted from the receive signals via a bank of narrowband filters. By using narrowband filters to extract each phase continuous waveform, the amount of noise competing with the waveform can be reduced.
39 Citations
35 Claims
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1. In a system where data is sent from a sending system to a receiving system over a band limited channel using a transmission waveform comprising a plurality of individual narrowband waveforms, each comprised of a plurality of substantially phase continuous events with a width based on the data word encoded thereby, a method for high speed data transfer between the sending system and the receiving system, comprising the steps of:
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generating a plurality of substantially phase continuous narrowband waveforms, each comprising a plurality of substantially phase continuous events with a width that is dependent on a data word to be transferred by that event and that lies between a minimum and maximum value selected for each of the plurality of narrowband waveforms so that each of said narrowband waveforms occupies a relatively small portion of the bandwidth of the band limited channel;
generating at least one substantially phase continuous pilot tone;
defining an epoch time;
combining said plurality of narrowband waveforms and said at least one pilot tone into a transmit waveform having the epoch time;
transmitting said transmit waveform to the receiving system, wherein a single frame of data is transferred during said epoch time after which a new epoch is begun that transfers an additional frame of data; and
while transmitting said transmit waveform, inserting a makeup time for any of said plurality of narrowband waveforms which fall short of said epoch time after all data words for the current frame of data have been transferred. - View Dependent Claims (2, 3, 4, 5, 6)
retrieving the data word to be sent by a selected one of said separate narrowband waveforms;
encoding the data word as an event that can be transmitted as part of the selected narrowband waveform so that the selected narrowband waveform is substantially phase continuous, and wherein the width of said event is determined by said data word to be sent and lies between the minimum and maximum frequency of the selected narrowband waveform;
transmitting said event so that the selected narrowband waveform is substantially phase continuous; and
repeating the above steps for each of said separate narrowband waveforms until a pre-determined time length is reached.
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3. A method of high speed data transfer as recited in claim 1 wherein the bandwidth of each narrowband waveform is less than about 33 percent of the bandwidth of the band limited channel.
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4. A method of high speed data transfer as recited in claim 1 wherein the bandwidth of each narrowband waveform is less than about 10 percent of the bandwidth of the band limited channel.
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5. A method of high speed data transfer as recited in claim 1 wherein the efficiency of the data transfer method when measured in bits per second per Hertz of bandwidth is greater than about 30 bits per second per Hertz of bandwidth.
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6. A method of high speed data transfer as recited in claim 1 wherein the efficiency of the data transfer method when measured in bits per second per Hertz of bandwidth is greater than about 50 bits per second per Hertz of bandwidth.
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7. In a system where data is sent from a sending system to a receiving system over a band limited channel using a transmission waveform comprising a plurality of individual narrowband waveforms, each comprised of a plurality of substantially phase continuous events with a width based on the data word encoded thereby, a method for high speed data transfer between the sending system and the receiving system, comprising the steps of:
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generating a plurality of substantially phase continuous narrowband waveforms, each comprising a plurality of substantially phase continuous events with a width that is dependent on a data word to be transferred by that event and that lies between a minimum and maximum value selected for each of the plurality of narrowband waveforms so that each of said narrowband waveforms occupies a relatively small portion of the bandwidth of the band limited channel;
generating at least one substantially phase continuous pilot tone;
combining said plurality of narrowband waveforms and said at least one pilot tone into a transmit waveform and transmitting said transmit waveform to the receiving system;
receiving the transmit waveform at the receiving system;
passing the transmit waveform to a pilot recovery circuit that recovers said at least one pilot tone;
phase locking a receiving clock to said recovered said at least one pilot tone;
passing the transmit waveform to a plurality of narrowband filters, each designed to recover one of said plurality of narrowband waveforms;
passing the output of each filter to a separate detector that detects the beginning and ending of the events so that the width of the events in the narrowband waveform recovered by the associated narrowband filter can be measured; and
based on the measured widths, recovering the data word transferred by a particular event. - View Dependent Claims (8, 9)
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10. A method for high speed transmission of a data stream from a sending system to a receiving system over a transmission channel with a given bandwidth, comprising the steps of:
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dividing the bandwidth of the transmission channel into a plurality of data channels;
defining a separate narrowband waveform to be transmitted on each of said plurality of data channels to carry data between the sending system and the receiving system, each of said narrowband waveforms having a defined minimum and maximum frequency that will be used to transmit information;
dividing the data stream into a plurality of data words to be transmitted from the sending system to the receiving system;
generating a data waveform comprising said separate narrowband waveforms by performing at least the steps of;
(a) retrieving a data word to be sent by a selected one of said separate narrowband waveforms;
(b) encoding the data word as an event that can be transmitted as part of the selected narrowband waveform so that the selected narrowband waveform is substantially phase continuous, and wherein the width of said event is determined by said data word to be sent and lies between the minimum and maximum frequency of the selected narrowband waveform;
(c) transmitting said event so that the selected narrowband waveform is substantially phase continuous; and
(d) repeating steps (a) through (c) for each of said separate narrowband waveforms until a pre-determined time length is reached; and
(e) adding a makeup time for any of said separate narrowband waveforms that fall short of said pre-determined time length after a pre-determined number of data words has been encoded for each of said separate narrowband waveforms; and
while said data waveform is being transmitted, combining said data waveform with at least one pilot tone and transmitting the resultant transmit waveform to the receiving system. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
receiving the transmit waveform at the receiving system;
passing the transmit waveform to a pilot recovery circuit that recovers said at least one pilot tone;
phase locking a receiving clock to said recovered at least one pilot tone;
passing the transmit waveform to a plurality of narrowband filters, each designed to recover one of said plurality of narrowband waveforms;
passing the output of each filter to a separate detector that detects the beginning and ending of the events so that the width of the events in the narrowband waveform recovered by the associated narrowband filter can be measured; and
based on the measured widths, recovering the data word transferred by a particular event.
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19. A method of high speed data transfer as recited in claim 18 wherein each detector is a zero-crossing detector that detects consecutive zero crossings of the event.
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20. A method of high speed data transfer as recited in claim 18 wherein each detector detects a zero crossing and a peak so that the time difference between the zero crossing and the peak can be measured.
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21. A method of high speed data transfer as recited in claim 10 further comprising the steps of:
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generating a second data waveform comprising a second set of a plurality narrowband waveforms, each of which comprises a plurality of events shaped so that each narrowband waveform is substantially phase continuous; and
transmitting said second data waveform over a second transmission channel.
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22. A method of high speed data transfer as recited in claim 10 wherein said events have a half sine wave shape.
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23. A method of high speed data transfer as recited in claim 10 wherein said events have a quarter sine wave shape.
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24. A method of high speed data transfer as recited in claim 10 further comprising the step of compressing the data stream prior to transmission to increase the effective throughput from the sending system to the receiving system.
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25. A method of high speed data transfer as recited in claim 10 further comprising the step of encoding the data stream prior to transmission to allow at least some errors that occur on reception to be corrected by the receiving system.
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26. A method for high speed transmission of a data stream from a sending system to a receiving system over a transmission channel with a given bandwidth, comprising the steps of:
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dividing the bandwidth of the transmission channel into a plurality of data channels;
defining a separate narrowband waveform to be transmitted on each of said plurality of data channels to carry data between the sending system and the receiving system, each of said narrowband waveforms having a defined minimum and maximum frequency that will be used to transmit information;
dividing the data stream into a plurality of data words to be transmitted from the sending system to the receiving system;
generating a data waveform comprising said separate narrowband waveforms by performing at least the steps of;
(a) retrieving a data word to be sent by a selected one of said separate narrowband waveforms;
(b) encoding the data word as an event that can be transmitted as part of the selected narrowband waveform so that the selected narrowband waveform is substantially phase continuous, and wherein the width of said event is determined by said data word to be sent and lies between the minimum and maximum frequency of the selected narrowband waveform and wherein the size of the data words varies depending on the separate narrowband waveforms selected in step (a);
(c) transmitting said event so that the selected narrowband waveform is substantially phase continuous; and
(d) repeating steps (a) through (c) for each of said separate narrowband waveforms until a pre-determined time length is reached;
while said data waveform is being transmitted, combining said data waveform with at least one pilot tone and transmitting the resultant transmit waveform to the receiving system.
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27. An apparatus for high speed data transmission over a transmission channel of a given bandwidth, comprising:
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means for generating a pilot tone;
means for generating a data waveform comprising a plurality of substantially phase continuous waveforms, said means for generating comprising;
first means for generating a plurality of individual events which are combined to create a first substantially phase continuous waveform, each event having a width that corresponds to a data word to be transmitted and that lies between a first minimum and a first maximums;
means for inserting a makeup time into the first substantially phase continuous waveform;
second means for generating a plurality of individual events which are combined to create a second substantially phase continuous waveform, each event having a width that corresponds to a data word to be transmitted and that lies between a second minimum and a second maximum; and
means for inserting a makeup time into the second substantially phase continuous waveform; and
means for combining said data waveform and said pilot tone to result in a transmission waveform which contains data encoded as a series of substantially phase continuous events and a phase continuous pilot tone. - View Dependent Claims (28, 29, 30, 31)
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32. An apparatus for high speed data transmission over a transmission channel of a given bandwidth, comprising:
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a pilot tone generator;
a plurality of waveform generators, each waveform generator comprising at least one direct digital synthesizer, and each waveform generator taking as an input a sequence of data words, at least some of which are drawn from a data stream that is to be transmitted, and producing as an output a sequence of substantially phase continuous events, each with a width dependent on one of the sequence of data words and each width falling between a minimum width and a maximum width that is set for the particular waveform generator that produced the event; and
a summing circuit that sums the output of the pilot tone generator and the plurality of waveform generators to produce a transmit waveform. - View Dependent Claims (33)
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34. An apparatus for receiving information via a transmit waveform comprising data words encoded into events of a plurality of narrowband waveforms, each event of the narrowband waveforms comprising a substantially phase continuous signal, the width of which is related to the data word encoded into the event, and wherein the transmit waveform further has encoded therein at least one pilot tone, said apparatus comprising:
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means for recovering the at least one pilot tone in order to produce a waveform having at least one frequency substantially equal to the at least one pilot tone;
means for phase locking a local receiver clock to the recovered at least one waveform;
means for filtering the transmit waveform to separate the plurality of narrowband waveforms contained therein so that each of the plurality of narrowband waveforms can be processed separately in order to extract the data encoded therein;
means for processing each of the plurality of narrowband waveforms comprising;
means for detecting the beginning and ending of an event of one of the plurality of narrowband waveforms;
means, responsive to said means for detecting and said receiver clock, for measuring the time difference between said beginning and ending; and
means for determining the data word encoded into the event from the measured time difference.
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35. An apparatus for receiving information via a transmit waveform comprising data words encoded into events of a plurality of narrowband waveforms, each event of the narrowband waveforms comprising a substantially phase continuous signal, the width of which is related to the data word encoded into the event, and wherein the transmit waveform further has encoded therein at least one pilot tone, said apparatus comprising:
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a pilot tone recovery circuit that takes as an input the transmit waveform and produces as an output at least one waveform that is substantially phase synchronous to the at least one pilot tone;
a phase locked receive clock that is phase locked to the output of the pilot tone recovery circuit;
a plurality of narrowband filters, each having a frequency response to pass one of the narrowband waveforms, in order to separate said one narrowband waveform for further processing;
a plurality of detectors, one connected to each of the plurality of narrowband filters, each detector being adapted to detect the beginning and end of an event;
a plurality of counters, one connected to each of the detectors, for measuring the time difference between the beginning and end of an event, each of said counters being connected to said receive clock; and
at least one data detector that extracts a data word from the time difference measured by said plurality of counters.
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Specification