High speed communications system for analog subscriber connections
DCFirst Claim
1. A high speed data transfer system for communicating between a digital data source and an analog subscriber connected to a digital telephone network by an analog loop comprising:
- an encoder coupled to said digital data source, said encoder converting an input from said data source into a series of codewords from a set of codewords corresponding to quantizer values utilized by said digital telephone network;
an interface for transmitting said series of codewords in digital form from said encoder to said digital telephone network; and
a decoder coupled by said analog loop to said digital telephone network, wherein said analog loop provides an analog signal to said decoder, which analog signal is an analog representation of said series of codewords, and wherein said decoder is responsive to said analog signal to reconstruct said series of codewords in digital form from said analog signal.
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Abstract
A new data communication system is described which enables data transmission over existing telephone lines at rates higher than possible with existing methods, including conventional modems. By using a novel asymmetric configuration of the two communication endpoints, the currently-accepted maximum theoretical limits on the data rate are no longer applicable. One endpoint is connected directly to a digital telephone network, whereas the other endpoint uses a conventional telephone connection. This reduces the transmission problem to compensation for a single telephone line interface and a single analog local loop. Device for providing this compensation and the required clock synchronization were also created, enabling a practical implementation of the system. The new system can achieve rates up to 64,000 bits-per-second and has broad utility in several active areas including wide-band audio transmission, video transmission, networking, facsimile transmission, and remote computer access.
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Citations
59 Claims
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1. A high speed data transfer system for communicating between a digital data source and an analog subscriber connected to a digital telephone network by an analog loop comprising:
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an encoder coupled to said digital data source, said encoder converting an input from said data source into a series of codewords from a set of codewords corresponding to quantizer values utilized by said digital telephone network; an interface for transmitting said series of codewords in digital form from said encoder to said digital telephone network; and a decoder coupled by said analog loop to said digital telephone network, wherein said analog loop provides an analog signal to said decoder, which analog signal is an analog representation of said series of codewords, and wherein said decoder is responsive to said analog signal to reconstruct said series of codewords in digital form from said analog signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A high speed data transfer method for a communications system connecting a data source to a subscriber, wherein said subscriber is connected to a digital telephone network by an analog loop and said data source is connected through a digital connection to said digital telephone network, said method comprising the steps of:
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selecting a subset of digital codewords from a set of digital telephone network codewords, said digital telephone network codewords corresponding to a set of quantization values applied at a line interface which couples said digital telephone network to said analog loop; mapping a data stream produced by said data source into a sequence of digital codewords from said subset of digital codewords; transmitting said sequence of codewords through said digital connection to said digital telephone network; converting said sequence of codewords into an analog signal at said line interface; and at said subscriber, reconstructing said sequence of codewords from said analog signal. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A method for transferring data between a first party having digital connectivity to a telephone system and an analog subscriber to said telephone system comprising the steps of:
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encoding digital data at the first party into a sequence of symbols from a set of quantization symbols corresponding to quantizer values utilized by said telephone system and utilized at a line interface connecting a digital portion of said telephone system to said analog subscriber; transmitting said sequence via said telephone system, said transmitting step comprising the step of converting said sequence at said line interface into an analog signal for reception by said subscriber; and at said analog subscriber, decoding the received analog signal to recover said digital data. - View Dependent Claims (47, 48)
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49. A high speed data transfer system for communicating between a digital data source and an analog subscriber connected to a digital telephone network by an analog loop, comprising:
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an encoder operatively associated with said digital data source, said encoder converting an input from said data source into a series of codewords from a set of codewords associated with quantizer values determined by said digital telephone network; an interface for transmitting said series of codewords in digital form from said encoder to said digital telephone network; a digital-to-analog converter located at a line interface between said digital telephone network and said analog loop, wherein said converter provides an analog signal to said subscriber over said analog loop, which analog signal is a representation of said series of codewords; and a decoder associated with said subscriber and connected to said analog loop, said decoder being responsive to said analog signal provided to said subscriber by said converter to reconstruct, from said analog signal, said input from said data source. - View Dependent Claims (50, 51)
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52. A high speed data transfer system for communicating digital data between data devices connected to a digital telephone network, where a data source is digitally connected to said network and a subscriber is connected via an analog subscriber line to said network, the transfer system comprising:
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an encoder responsive to said data source, said encoder converting data from said data source into a series of codewords selected from a subset of a set of codewords corresponding to quantizer values utilized by said network, each of said codewords corresponding to an analog level generated by a digital-to-analog converter device within said network; an interface for communicating said series of codewords from said encoder to said network, wherein said digital-to-analog converter converts said series of codewords into an analog signal, which analog signal is coupled to said analog subscriber line; and a decoder responsive to said analog signal to reconstruct said series of codewords from said analog signal.
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53. A high speed data transfer method for communicating digital data between data devices connected to a digital telephone network, where a data source is digitally connected to said network and a data recipient is connected via an analog subscriber line to said network, said method comprising the steps of:
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selecting a subset of codewords from a set of codewords corresponding to analog levels generated by a digital-to-analog converter within said network; mapping a data stream produced by said data source into a sequence of digital codewords from said subset of digital codewords corresponding to quantizer values utilized by said network; converting said sequence of codewords into a corresponding sequence of analog levels at said digital-to-analog converter; sending said sequence of analog levels to said data recipient; at said data recipient, reconstructing said sequence of codewords from said sequence of analog levels; and converting said reconstructed sequence of codewords into said data stream.
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54. A method for transferring digital data from a first party, having digital connectivity to a telephone network, to a second party having analog connectivity to said telephone networks comprising the steps of:
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encoding digital data at the first party into a sequence of codewords selected from a subset of codewords corresponding to quantizer values utilized by said network and analog levels generated by a digital-to-analog converter device within said network; transmitting said sequence of codewords via said telephone network to a line interface that includes said digital-to-analog converter device, said line interface being coupled to said second party; converting said sequence of codewords into a sequence of analog levels at said line interface; receiving said sequence of analog levels at said second party; recovering said digital data from said received sequence of analog levels.
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55. A high speed data transfer system for communicating data over a connection, wherein the connection includes an analog subscriber loop that is coupled by a line interface to a digital telephone network, comprising:
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an encoder coupled to said digital telephone network, wherein said encoder converts an input from a data source into a digital series of codewords, said codewords being selected from a subset of a group of codewords corresponding to quantizer values utilized by said digital network and associated with said line interface, and transmits said digital series of codewords and to said digital telephone network, said digital series of codewords being converted to an analog signal at said line interface; and a decoder coupled to said analog subscriber loop, wherein said decoder receives said analog signal from said line interface over said analog subscriber loop and reconstructs said digital series of codewords from said analog signal.
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56. A high speed data transfer method for communicating data over a connection, wherein the connection includes an analog subscriber loop that is coupled by a line interface to a digital telephone network, comprising:
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encoding an input from a data source into a digital series of codewords, said codewords being selected from a subset of a group of codewords corresponding to quantizer values utilized by said digital network associated with said line interface; transmitting said encoded digital series of codewords over said digital telephone network to said line interface; converting said encoded digital series of codewords into an analog signal at said line interface; transmitting said analog signal over said analog subscriber loop from said line interface; receiving said analog signal from said analog subscriber loop; and reconstructing said digital series of codewords from said received analog signal. - View Dependent Claims (57, 58, 59)
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Specification