EP0471945A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for transmission of local area network signals over unshielded twisted pairs
Assignee: Digital Equipment Corp
•
Filing: 1991-06-24
•
Granted: —
•
Expires: 2011-06-24
Abstract
Abstract Apparatus, and a related method for its operation, for transmitting binary data at high speed through unshielded twisted pairs of conductors intended for a much lower data speed and bandwidth. By using a combination of demultiplexing into multiple data channels, encoding the binary signals into a modified three-level duobinary code, and filtering the signals before transmission, data rates as high as 125 megabits per second can be transmitted over four unshielded twisted pairs of conductors. Two illustrative forms of the invention are disclosed, one of which uses two channels for transmission over two twisted pairs in each direction of transmission. The other form of the invention uses four data channels, to further reduce the transmitted bandwidth in each channel, and four twisted pairs of conductors, for transmission in both directions by means of hybrid circuits interconnecting the transmitter and receiver functions at each end of the channels.
Inventors
- 👤 Simon A. Ginzburg
- 👤 John M. Rieger
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 12:32
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4917; H04L25/4923
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
119 words
A method for transmitting a stream of high-speed binary data over twisted pairs of unshielded conductors (20,22), comprising the steps of: demultiplexing the binary data into at least two parallel channels (10, 12), where each channel carries signals at a lower bandwidth than the original stream of binary data; encoding (16, 18) the binary data in each of the parallel channels into an n-level code, where n is at least three and the bandwidth of the signals in each channel is further reduced by a factor of approximately two or more; lowpass filtering (48) the n-level code in each channel to further reduce the bandwidth; and transmitting the signals in each channel over an unshielded twisted pair of conductors.
Claim 2
Dependent Claim
54 words
A method as defined in claim 1, and further comprising the steps of: compensating for the frequency response of each twisted pair of conductors; decoding n-level signals received over each twisted pair of conductors into corresponding binary signals on multiple channels; and multiplexing the multiple channels into a single high-speed stream of binary data.
Claim 3
Dependent Claim
19 words
A method as defined in claim 1, wherein: the encoding step includes forming a three-level modified duobinary (46) code.
Claim 4
Dependent Claim
39 words
A method as defined in claim 3, wherein the step of forming a three-level modified duobinary code includes: subtractively combining the binary data stream with a time-delayed replica of the binary data stream, to yield the modified duobinary code.
Claim 5
Dependent Claim
44 words
A method as defined in claim 4, wherein the step of forming a three-level modified duobinary code further includes: precoding the binary data, prior to the step of subtractively combining, to form a precoded binary data stream that eliminates error propagation and simplifies decoding.
Claim 6
Dependent Claim
34 words
A method as defined in claim 2, wherein: the encoding step includes forming a three-level modified duobinary code; and the decoding step includes transforming a received three-level modified duobinary code into a binary code.
Claim 7
Dependent Claim
39 words
A method as defined in claim 6, wherein the step of forming a three-level modified duobinary code includes: subtractively combining the binary data stream with a time-delayed replica of the binary data stream, to yield the modified duobinary code.
Claim 8
Dependent Claim
26 words
A method as defined in claim 7, wherein the step or transforming the three-level modified duobinary code into a binary code includes: rectifying the three-level code.
Claim 9
Dependent Claim
44 words
A method as defined in claim 8, wherein the step of forming a three-level modified duobinary code further includes: precoding the binary data, prior to the step of subtractively combining, to form a precoded binary data stream that eliminates error propagation and simplifies decoding.
Claim 10
Independent Claim
150 words
A method for transmitting a stream of high-speed binary data over twisted pairs of conductors, comprising the steps of: demultiplexing the binary data into two parallel channels, where each channel carries signals at half of the bandwidth of the original stream of binary data: encoding the binary data in each of the parallel channels into a 3-level modified duobinary code, where the bandwidth of the signals in each channel is further reduced by a factor of approximately two; lowpass filtering the n-level code in each channel to further reduce the bandwidth: transmitting the signals in each channel over an unshielded twisted pair of conductors; receiving the transmitted signals; compensating for the frequency response of each twisted pair of conductors; decoding the 3-level signals received over each twisted pair of conductors into corresponding binary signals on two channels; and multiplexing the two channels into a single high-speed stream of binary data.
Claim 11
Dependent Claim
65 words
A method as defined in claim 10, wherein: the original data stream is processed at a rate of approximately 125 megabits per second; the demultiplexing step provides two channels at approximately 62.5 megabits per second; the encoding step reduced the effective speed of each channel to approximately 31.25 megabits per second; and the filtering step reduces the bandwidth of each channel to approximately 30 megahertz.
Claim 12
Dependent Claim
67 words
A method as defined in claim 10, wherein: the method is used in a fiber distributed data interface (FDDI) communication network, using a signal format in which each four-bit data code is encoded into a five-bit NRZI (nonreturn to zero invert on ones) code in accordance with coding scheme referred to as 4B/5B; and the demultiplexing step retains the 4B/5B format in each of its resultant channels.
Claim 13
Dependent Claim
132 words
Digital signal communication apparatus for transmitting a stream of high-speed binary data over twisted pairs of conductors (20, 22), the apparatus comprising: demultiplexing means (14), for separating the binary data into at least two parallel channels (10, 12), where each channel carries signals at a lower bandwidth than the original stream of binary data; modulation means (16, 18), for encoding the binary data in each of the parallel channels into an n-level code, where n is at least three and the bandwidth of the signals in each channel is further reduced by a factor of approximately two or more; lowpass filter means (48), for further reducing the bandwidth of the n-level code in each channel; and means (14') for transmitting the signals in each channel over an unshielded twisted pair of conductors.
Claim 14
Dependent Claim
61 words
Apparatus as defined in claim 13, and further comprising: equalizer means (62), for compensating for the frequency response of each twisted pair of conductors; demodulator means, for decoding n-level signals received over each twisted pair of conductors into corresponding binary signals on multiple channels; and multiplexer means (40), for multiplexing the multiple channels into a single high-speed stream of binary data.
Claim 15
Dependent Claim
19 words
Apparatus as defined in claim 13, wherein: the modulation means includes means for forming a three-level modified duobinary code.
Claim 16
Dependent Claim
40 words
Apparatus as defined in claim 15, wherein the means for forming a three-level modified duobinary code includes: means for subtractively combining the binary data stream with a time-delayed replica of the binary data stream, to yield the modified duobinary code.
Claim 17
Dependent Claim
43 words
Apparatus as defined in claim 15, wherein the means for forming a three-level modified duobinary code further includes: means for precoding the binary data, prior to the subtractively combining it with delayed data, to form a precoded binary data stream that simplifies decoding.
Claim 18
Dependent Claim
37 words
Apparatus as defined in claim 14, wherein: the modulation means includes means for forming a three-level modified duobinary code; and the demodulation means includes means for transforming a received three-level modified duobinary code into a binary code.
Claim 19
Dependent Claim
40 words
Apparatus as defined in claim 18, wherein the means for forming a three-level modified duobinary code includes: means for subtractively combining the binary data stream with a time-delayed replica of the binary data stream, to yield the modified duobinary code.
Claim 20
Dependent Claim
27 words
Apparatus as defined in claim 19, wherein the means for transforming the three-level modified duobinary code into a binary code includes: means for rectifying the three-level code.
Claim 21
Dependent Claim
41 words
Apparatus as defined in claim 20, wherein the means for forming a three-level modified duobinary code further includes: means for precoding the binary data, prior to the step of subtractively combining, to form a precoded binary data stream that simplifies decoding.
Claim 22
Dependent Claim
191 words
Digital signal communication apparatus for transmitting a stream of high-speed binary data over twisted pairs of conductors, the apparatus comprising: means for demultiplexing the binary data into four parallel channels, where each channel carries signals at one-fourth the bandwidth of the original stream of the binary data; modulator means, for encoding the binary data in each of the parallel channels into a 3-level duobinary code, where the bandwidth of the signals in each channel is further reduced by a factor of approximately two; means for lowpass filtering the n-level code in each channel to further reduce the bandwidth; and means for transmitting the signals in each channel over an unshielded twisted pair of conductors, a hybrid circuit for each twisted pair of conductors, to effect sharing of the pair between transmitting and receiving functions; means for receiving the transmitted signals; equalizer means, for compensating for the frequency response of each twisted pair of conductors; demodulator means, for decoding the 3-level signals received over each twisted pair of conductors into corresponding binary signals on four channels; and multiplexer means, for multiplexing the four channels into a single high-speed stream of binary data.
Claim 23
Independent Claim
147 words
A method for transmitting a stream of high-speed binary data over twisted pairs of conductors, comprising the steps of: demultiplexing the binary data into two parallel channels, where each channel carries signals at half of the bandwidth of the original stream of binary data; encoding the binary data in each of the parallel channels into a 3-level modified duobinary code, where the bandwidth of the signals in each channel is further reduced by a factor of approximately two; lowpass filtering the n-level code in each channel to further reduce the bandwidth; transmitting the signals in each channel over an unshielded twisted pair of conductors; receiving the transmitted signals; decoding, using a decoder based on the Viterbi algorithm, the 3-level signals received over each twisted pair of conductors into corresponding binary signals on two channels; and multiplexing the two channels into a single high-speed stream of binary data.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.