Patent EP0197263A2 successfully refreshed from Google Patents.
EP0197263A2
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Method and apparatus for deskewing WDM data transmitted through a dispersive medium
Assignee: International Business Machines Corp
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Filing: 1986-02-14
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Granted: —
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Expires: 2006-02-14
Abstract
Abstract When a byte of digital data is transmitted through a dispersive medium using frequency or wavelength division multiplexing (WDM) techniques, individual bits in the byte are normally delayed different amounts of time. This is referred to as bit skew. WDM apparatus is described along with a system for deskewing WDM data received after transit through a dispersive medium. Two bits in a given byte of data are detected. The relative times of arrival of the remaining bits in a byte are predicted using the relative delay between the two detected bits and the known frequency-related dispersion characteristics of the transmission medium. Certain bits in each received byte may be delayed using clock delay lines or registers to reduce the amount of time skew between the various bits in a byte.
Inventors
- 👤 Lee Clyde Haas
- 👤 Mitchell Levy Loeb
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 14:30
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29304; G02B6/29305; G02B6/2931; G02B6/29346; G02B6/29361; G02B6/29362; G02B6/29365; G02B6/29367; G02B6/29379; G02B6/2938; H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2513; H04J; H04J14/00; H04J14/02; H04J14/03; H04J14/0307
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
98 words
A method for deskewing the individual bits in a byte of data transmitted in parallel bit channels using frequency division multiplexing through a medium having known frequency-related dispersion characteristics, said method comprising the steps of: detecting the arrival at a deskewing location of bits in each of parallel bit channels; determining the relative delay between two detected bits in predetermined bit channels; establishing the relative times of arrival of bits in the remaining bit channels as a function of the determined relative delay, the frequencies of the remaining channels and the known frequency-related dispersion characteristics of the medium.
Claim 2
Independent Claim
98 words
A method for deskewing the individual bits in a byte of data transmitted in parallel bit channels using frequency division multiplexing through a medium having known frequency-related dispersion characteristics, said method comprising the steps of: detecting the arrival at a deskewing location of bits in each of parallel bit channels; determining the relative delay between two detected bits in predetermined bit channels; establishing the relative times of arrival of bits in the remaining bit channels as a function of the determined relative delay, the frequencies of the remaining channels and the known frequency-related dispersion characteristics of the medium.
Claim 3
Dependent Claim
25 words
A method as defined in Claim 1 wherein the two detected bits are the first two bits to arrive in a given byte of data.
Claim 4
Independent Claim
86 words
A method as defined in either of Claims 1 or 2 including the additional steps of: establishing the relative delay between the different bit channels for each byte of data; generating delay clock signals for certain of said bit channels as a function of the established relative delay; and passing the bits in the various bit channels to signal utilizing circuits under the control of the delay clock signals to reduce the time skew between the first and last bits to arrive in a given byte.
Claim 5
Independent Claim
102 words
A system for deskewing the individual bits in a byte of data transmitted in parallel bit channels using frequency division multiplexing through a medium having known frequency-related dispersion characteristics, said system including: means for detecting the arrival of bits in each of the parallel bit channels; means for determining the relative delay between two detected bits in predetermined ones of the bit channels; and means for establishing the relative times of arrival of bits in the remaining bit channels as a function of the determined relative delay, the frequencies of the remaining channels and the known frequency-related dispersion characteristics of the medium.
Claim 6
Independent Claim
102 words
A system for deskewing the individual bits in a byte of data transmitted in parallel bit channels using frequency division multiplexing through a medium having known frequency-related dispersion characteristics, said system including: means for detecting the arrival of bits in each of the parallel bit channels; means for determining the relative delay between two detected bits in predetermined ones of the bit channels; and means for establishing the relative times of arrival of bits in the remaining bit channels as a function of the determined relative delay, the frequencies of the remaining channels and the known frequency-related dispersion characteristics of the medium.
Claim 7
Dependent Claim
49 words
A system as defined in Claim 4 further including means for delaying the further transmission of bits in certain of the bit channels as a function of the times of arrival of bits in those channels relative to time of arrival of bits in the slowest of the channels.
Claim 8
Dependent Claim
41 words
A system as defined in Claim 5 wherein said delaying means further includes: a plurality of signal delaying elements, each element receiving the output of one of the bit channels; and means for generating clock signals for said signal delaying elements.
Claim 9
Independent Claim
104 words
A method for deskewing bits in successive bytes of data transmitted in parallel through a medium having known frequency-related dispersion characteristics by means of frequency division multiplexing, said method comprising the steps of: demultiplexing the transmitted data at a receiving location to produce bit streams in parallel channels; determining the relative delay between two predetermined bits in a given byte of data, said bits being in different channels; and establishing the relative times of arrival of the bits in the remaining channels as a function of the determined relative delay, the frequencies of the remaining channels and the frequency-related dispersion characteristics of the medium.
Claim 10
Independent Claim
104 words
A method for deskewing bits in successive bytes of data transmitted in parallel through a medium having known frequency-related dispersion characteristics by means of frequency division multiplexing, said method comprising the steps of: demultiplexing the transmitted data at a receiving location to produce bit streams in parallel channels; determining the relative delay between two predetermined bits in a given byte of data, said bits being in different channels; and establishing the relative times of arrival of the bits in the remaining channels as a function of the determined relative delay, the frequencies of the remaining channels and the frequency-related dispersion characteristics of the medium.
Claim 11
Dependent Claim
23 words
A method as defined in Claim 7 wherein the two predetermined bits are the first two bits to arrive in a given byte.
Claim 12
Dependent Claim
47 words
A method as defined in Claim 8 further including the step of delaying the further transmission of certain of the bits in certain channels in a dernul- tiplexed byte to reduce the amount of skew between bits in the same byte prior to utilization of the data.
Claim 13
Independent Claim
58 words
A method as defined in either of Claims 8 or 9 wherein one of the two predetermined bits is multiplexed at a frequency known to have the highest group velocity for the given medium and the other of the predetermined bits is multiplexed at a frequency known to have the second highest group velocity for the given medium.
Claim 14
Independent Claim
96 words
A system for deskewing individual bits in successive bytes of data transmitted in parallel through a medium having known frequency-related dispersion characteristics using frequency division multiplexing, said system including: means for demultiplexing the transmitted data to produce parallel bit streams in parallel channels; means for determining the relative delay in the arrival of two bits in different predetermined channels; and means for establishing the relative times of arrival of bits in the remaining bit channels as a function of the relative delay, the frequencies of the remaining channels and the known dispersion characteristics of the medium.
Claim 15
Independent Claim
96 words
A system for deskewing individual bits in successive bytes of data transmitted in parallel through a medium having known frequency-related dispersion characteristics using frequency division multiplexing, said system including: means for demultiplexing the transmitted data to produce parallel bit streams in parallel channels; means for determining the relative delay in the arrival of two bits in different predetermined channels; and means for establishing the relative times of arrival of bits in the remaining bit channels as a function of the relative delay, the frequencies of the remaining channels and the known dispersion characteristics of the medium.
Claim 16
Dependent Claim
41 words
A system as defined in Claim 11 further including means for delaying the bits in certain of the channels to reduce the amount of skew between bits in the same byte prior to further utilization of the data in the byte.
Claim 17
Dependent Claim
68 words
A system as defined in Claim 12 wherein said delaying means comprises: a plurality of signal delaying elements, each of said elements receiving the output of one of the bit channels, and. means for generating clock signals for said signal delaying elements to clock data through said elements at times dependent upon the relative delays so as to reduce the time skew between bits in the various channels.
References Cited (Backward Citations)
No citation records indexed.
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