Patent US3623041A successfully refreshed from Google Patents.
US3623041A
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Method and apparatus for encoding and decoding digital data
Assignee: International Business Machines Corp
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Filing: 1969-07-22
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Granted: 1971-11-23
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Expires: 1989-07-22
Abstract
Abstract Method and apparatus are disclosed for processing and storage of binary information on a medium having two separately identifiable levels or states and having a plurality of nearly uniform bit cells. Encoding is accomplished by writing a transition between the two states at the center of each bit cell representing a ''''one'''' unless the cell is preceded by a ''''zero one'''' and followed by a ''''zero.'''' Transitions are written at the leading edges of bit cells which are to represent a ''''zero'''' if there is not a ''''one'''' or a ''''zero'''' written in the preceding cell or a ''''one'''' dropped in the preceding cell. In decoding, the data transitions detected at the centers of bit cells are separated as ''''ones'''' while bit cells having a transition at the leading edge thereof are considered to represent ''''zero.'''' Bit cells which do not have a transition either at the center thereof or at the leading edge thereof are determined to represent ''''zero'''' unless the immediately following bit cell is similarly absent a transition at the leading edge or center thereof, in which case a ''''one'''' is inserted into the first of the two bit cells absent any transitions.
Inventors
- 👤 David L Macdougall Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:28
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1423; H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4904
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
244 words
A method of communicating binary information as identifiable signal indicia within a succession of arbitrarily defined bit cell intervals comprising the steps of: communicating one binary characterization in selected ones of the bit cell intervals by producing a signal indicium at the midpoint of only those of the selected bit cell intervals not communicated immediately following a pair of bit cell intervals having the one binary characterization and the other binary characterization therein and immediately before a bit cell interval which is to have the other binary characterization therein; communicating the other binary characterization in bit cell intervals other than said selected ones by producing a signal indicium aT the leading edge of only those of said other bit cell intervals not communicated immediately following a bit cell interval having a signal indicium therein; identifying the communicated bit cell intervals having a signal indicium at the midpoint as representing the one binary characterization; identifying the communicated bit cell intervals having a signal indicium at the leading edge as representing the other binary characterization; identifying the communicated bit cell intervals which do not have a signal indicium and which are communicated immediately following a bit cell interval having a signal indicium therein as representing the other binary characterization; and identifying the communicated bit cell intervals which do not have a signal indicium and which are communicated immediately before a bit cell interval which does not have a signal indicium as representing the one binary characterization.
Claim 2
Independent Claim
244 words
A method of communicating binary information as identifiable signal indicia within a succession of arbitrarily defined bit cell intervals comprising the steps of: communicating one binary characterization in selected ones of the bit cell intervals by producing a signal indicium at the midpoint of only those of the selected bit cell intervals not communicated immediately following a pair of bit cell intervals having the one binary characterization and the other binary characterization therein and immediately before a bit cell interval which is to have the other binary characterization therein; communicating the other binary characterization in bit cell intervals other than said selected ones by producing a signal indicium aT the leading edge of only those of said other bit cell intervals not communicated immediately following a bit cell interval having a signal indicium therein; identifying the communicated bit cell intervals having a signal indicium at the midpoint as representing the one binary characterization; identifying the communicated bit cell intervals having a signal indicium at the leading edge as representing the other binary characterization; identifying the communicated bit cell intervals which do not have a signal indicium and which are communicated immediately following a bit cell interval having a signal indicium therein as representing the other binary characterization; and identifying the communicated bit cell intervals which do not have a signal indicium and which are communicated immediately before a bit cell interval which does not have a signal indicium as representing the one binary characterization.
Claim 3
Independent Claim
279 words
A method of encoding binary ''''ones'''' and ''''zeros'''' on a communication medium and thereafter detecting the ''''ones'''' and ''''zeros'''' from the communication medium, the communication medium exhibiting two separately identifiable states and being considered to be arbitrarily divided into a plurality of nearly uniform bit cells, comprising the steps of: producing a transition between the separately identifiable states at the midpoint of each bit cell which is to represent a ''''one'''' except where the bit cell is immediately preceded by a pair of bit cells representing ''''zero one'''' and immediately followed by a bit cell which is to represent a ''''zero'''' ; producing a transition between the separately identifiable states at the leading edge of each bit cell which is to represent a ''''zero'''' except where the bit cell is immediately preceded by a bit cell having a transition at the leading edge or the midpoint thereof; detecting those bit cells which have a transition at the midpoint and identifying the detected bit cells as representing a ''''one'''' ; detecting those bit cells which have a transition at the leading edge and identifying the detected bit cells as representing a ''''zero''''; identifying the remaining bit cells which do not have a transition at the leading edge or the midpoint as representing a ''''zero'''' unless the bit cell is followed by a bit cell which does not have a transition at the leading edge or the midpoint; and identifying the remaining bit cells which do not have a transition at the leading edge or the midpoint and which are followed by a bit cell which does not have a transition at the leading edge or the midpoint as a ''''one.''''
Claim 4
Independent Claim
279 words
A method of encoding binary ''''ones'''' and ''''zeros'''' on a communication medium and thereafter detecting the ''''ones'''' and ''''zeros'''' from the communication medium, the communication medium exhibiting two separately identifiable states and being considered to be arbitrarily divided into a plurality of nearly uniform bit cells, comprising the steps of: producing a transition between the separately identifiable states at the midpoint of each bit cell which is to represent a ''''one'''' except where the bit cell is immediately preceded by a pair of bit cells representing ''''zero one'''' and immediately followed by a bit cell which is to represent a ''''zero'''' ; producing a transition between the separately identifiable states at the leading edge of each bit cell which is to represent a ''''zero'''' except where the bit cell is immediately preceded by a bit cell having a transition at the leading edge or the midpoint thereof; detecting those bit cells which have a transition at the midpoint and identifying the detected bit cells as representing a ''''one'''' ; detecting those bit cells which have a transition at the leading edge and identifying the detected bit cells as representing a ''''zero''''; identifying the remaining bit cells which do not have a transition at the leading edge or the midpoint as representing a ''''zero'''' unless the bit cell is followed by a bit cell which does not have a transition at the leading edge or the midpoint; and identifying the remaining bit cells which do not have a transition at the leading edge or the midpoint and which are followed by a bit cell which does not have a transition at the leading edge or the midpoint as a ''''one.''''
Claim 5
Dependent Claim
52 words
The method of claim 2, wherein: the communication media is initially in one of the two, separately identifiable states; and the direction of each of the produced transitions is from the one of the separately identifiable states the medium is in immediately prior to the transition, to the other separately identifiable state.
Claim 6
Dependent Claim
127 words
The method of claim 2, wherein: the communication medium comprises a magnetic recording medium which exhibits a hysteresis characteristic having two stable states of remanence and which is considered to be arbitrarily arranged into at least one lineal track, each track being considered as comprising a succession of contiguous bit cells of nearly uniform length; and the producing of a transition between the separately identifiable states of the communication medium comprises imposing a magnetic field upon said magnetic recording medium to first impress one of said remanent states upon the medium, moving said magnetic field longitudinally along said track, and changing the direction of said magnetic field to cause the medium to undergo a transition at the point of change to the other of said remanent states.
Claim 7
Independent Claim
321 words
A system for processing binary information for communication on a medium having two, separately identifiable states, comprising: a source of binary informaTion; clocking means for forming a plurality of bit cells of substantially uniform time durations; logic means responsive to the binary information from the source and to the clocking means to provide an output on said medium such that one bit of binary information is communicated in each of said bit cells, said output responding to those of said bits of one binary characterization by providing a transition between said separately identifiable states at the midpoint of each corresponding bit cell except where the bit cell is immediately preceded by a pair of bit cells containing bits of the other binary characterization and the one binary characterization and immediately followed by a bit cell containing a bit of the other binary characterization, and responding to those of said bits of the other binary characterization by providing a transition between said separately identifiable states at the leading edge of only those of the corresponding bit cells which immediately follow a bit cell having no transition therein; and means for recovering said binary information from said output by responding to said transitions to detect the boundaries of said bit cells, said recovering means responding to those of said transitions occurring at the midpoint of a bit cell to detect said one binary characterization in each such bit cell and to those of said transitions occurring at the leading edge of a bit cell to detect said other binary characterization in each such bit cell, said recovering means further responding to those bit cells without a transition at the midpoint or leading edge thereof and to the immediately preceding bit cell to detect said other binary characterization when the immediately preceding bit cell contains a transition and to detect said one binary characterization when the immediately preceding bit cell is absent a transition.
Claim 8
Independent Claim
321 words
A system for processing binary information for communication on a medium having two, separately identifiable states, comprising: a source of binary informaTion; clocking means for forming a plurality of bit cells of substantially uniform time durations; logic means responsive to the binary information from the source and to the clocking means to provide an output on said medium such that one bit of binary information is communicated in each of said bit cells, said output responding to those of said bits of one binary characterization by providing a transition between said separately identifiable states at the midpoint of each corresponding bit cell except where the bit cell is immediately preceded by a pair of bit cells containing bits of the other binary characterization and the one binary characterization and immediately followed by a bit cell containing a bit of the other binary characterization, and responding to those of said bits of the other binary characterization by providing a transition between said separately identifiable states at the leading edge of only those of the corresponding bit cells which immediately follow a bit cell having no transition therein; and means for recovering said binary information from said output by responding to said transitions to detect the boundaries of said bit cells, said recovering means responding to those of said transitions occurring at the midpoint of a bit cell to detect said one binary characterization in each such bit cell and to those of said transitions occurring at the leading edge of a bit cell to detect said other binary characterization in each such bit cell, said recovering means further responding to those bit cells without a transition at the midpoint or leading edge thereof and to the immediately preceding bit cell to detect said other binary characterization when the immediately preceding bit cell contains a transition and to detect said one binary characterization when the immediately preceding bit cell is absent a transition.
Claim 9
Dependent Claim
121 words
A system in accordance with claim 5, wherein said logic means additionally comprises: first blocking means responsive to a succession of four bit cells in which the outer two bit cells are to represent the other binary characterization and the inner two bit cells are to represent the one binary characterization for preventing the occurrence of an output transition in the second inner bit cell; storage means for indicating whether the output provided for the immediately preceding bit cell contained a transition therein; and second blocking means responsive to said storage means for preventing the occurrence of output transitions in those of said bit cells corresponding to said other binary characterization which immediately follow a bit cell having a transition therein.
Claim 10
Dependent Claim
262 words
In a system in which binary information is communicated in the form of transitions between two separately identifiable states of a communication medium within a succession of substantially uniform bit cells thereof, those bit cells which have a transition substantially at the midpoint thereof representing a ''''one'''' bit, those bit cells which have a transition substantially at the leading edge thereof representing a ''''zero'''' bit, and those bit cells which do not include a transition representing a ''''zero'''' bit if the immediately following bit cell includes a transition and a ''''one'''' bit if the immediately following bit cell does not include a transition, an arrangement for detecting the communicated binary data comprising: means responsive to the communication medium for generating separate sets of ''''one'''' and ''''zero'''' pulses in coincidence with the transitions at the midpoints an leading edges of the bit cells respectively; first shift register means having a plurality of stages and responsive to the ''''one'''' pulses to store a representation of the presence or absence of a ''''one'''' pulse in each bit cell; second shift register means having a plurality of stages and responsive to the ''''zero'''' pulses to store a representation of the presence or absence of a ''''zero'''' PULSE in each bit cell; output means coupled to the first shift register means to receive a representation of each ''''one'''' pulse advanced through the first shift register means; and means responsive to selected stages in the first and second shift register means for providing a ''''one'''' representation to the output means whenever the selected stages simultaneously assume predetermined states.
Claim 11
Dependent Claim
262 words
In a system in which binary information is communicated in the form of transitions between two separately identifiable states of a communication medium within a succession of substantially uniform bit cells thereof, those bit cells which have a transition substantially at the midpoint thereof representing a ''''one'''' bit, those bit cells which have a transition substantially at the leading edge thereof representing a ''''zero'''' bit, and those bit cells which do not include a transition representing a ''''zero'''' bit if the immediately following bit cell includes a transition and a ''''one'''' bit if the immediately following bit cell does not include a transition, an arrangement for detecting the communicated binary data comprising: means responsive to the communication medium for generating separate sets of ''''one'''' and ''''zero'''' pulses in coincidence with the transitions at the midpoints an leading edges of the bit cells respectively; first shift register means having a plurality of stages and responsive to the ''''one'''' pulses to store a representation of the presence or absence of a ''''one'''' pulse in each bit cell; second shift register means having a plurality of stages and responsive to the ''''zero'''' pulses to store a representation of the presence or absence of a ''''zero'''' PULSE in each bit cell; output means coupled to the first shift register means to receive a representation of each ''''one'''' pulse advanced through the first shift register means; and means responsive to selected stages in the first and second shift register means for providing a ''''one'''' representation to the output means whenever the selected stages simultaneously assume predetermined states.
Claim 12
Dependent Claim
118 words
An arrangement in accordance with claim 7, wherein the means for generating separate sets of ''''one'''' and ''''zero'''' pulses includes: means responsive to each transition of the communication medium for generating a pulse in coincidence therewith; means responsive to the generated pulses for generating a reference signal in synchronism therewith; first gating means responsive to the reference signal and to the generated pulses for passing those pulses which occur during the center portion of each bit cell to the first shift register means; and second gating means responsive to the reference signal and to the generated pulses for passing those pulses which occur at the opposite edge portions of each bit cell to the second shift register means.
Claim 13
Independent Claim
152 words
A method of communicating one of two different characterizations of binary information as identifiable signal indicia within a succession of arbitrarily defined bit cell intervals comprising the steps of: communicating the one binary characterization in selected ones of the bit cell intervals by producing a signal indicium at the midpoint of only those of the selected bit cell intervals not communicated immediately following a pair of bit cell intervals having the one binary characterization and the other binary characterization therein and immediately before a bit cell interval which is to have the other binary characterization therein; identifying the communicated bit cell intervals having a signal inidicium at the midpoint as representing the one binary characterization; and identifying the communicated bit cell intervals which do not have a signal indicium and which are communicated immediately before a bit cell interval which does not have a signal indicium as representing the one binary characterization.
Claim 14
Independent Claim
152 words
A method of communicating one of two different characterizations of binary information as identifiable signal indicia within a succession of arbitrarily defined bit cell intervals comprising the steps of: communicating the one binary characterization in selected ones of the bit cell intervals by producing a signal indicium at the midpoint of only those of the selected bit cell intervals not communicated immediately following a pair of bit cell intervals having the one binary characterization and the other binary characterization therein and immediately before a bit cell interval which is to have the other binary characterization therein; identifying the communicated bit cell intervals having a signal inidicium at the midpoint as representing the one binary characterization; and identifying the communicated bit cell intervals which do not have a signal indicium and which are communicated immediately before a bit cell interval which does not have a signal indicium as representing the one binary characterization.
Claim 15
Dependent Claim
181 words
In a system in which one of two different characterizations of binary information is communicated within selected ones of a succession of arbitrarily defined bit cell intervals by producing a signal indicium at the midpoint of each of the selected ones of the bit cell intervals except where the selected bit cell interval follows a pair of bit cell intervals having the one binary characterization and the other binary characterization therein and precedes a bit cell interval which is to have the other binary characterization therein, an arrangement for detecting the communicated one binary characterization comprising: means responsive to those bit cell intervals having a signal indicium at the midpoint for identifying each such bit cell interval as representing the one binary characterization; and means responsive to those bit cell intervals which do not have a signal indicium at the leading edge or the midpoint and which are followed by a bit cell interval which does not have a signal indicium at the leading edge or the midpoint for identifying each such bit cell interval as representing the one binary characterization.
Claim 16
Dependent Claim
181 words
In a system in which one of two different characterizations of binary information is communicated within selected ones of a succession of arbitrarily defined bit cell intervals by producing a signal indicium at the midpoint of each of the selected ones of the bit cell intervals except where the selected bit cell interval follows a pair of bit cell intervals having the one binary characterization and the other binary characterization therein and precedes a bit cell interval which is to have the other binary characterization therein, an arrangement for detecting the communicated one binary characterization comprising: means responsive to those bit cell intervals having a signal indicium at the midpoint for identifying each such bit cell interval as representing the one binary characterization; and means responsive to those bit cell intervals which do not have a signal indicium at the leading edge or the midpoint and which are followed by a bit cell interval which does not have a signal indicium at the leading edge or the midpoint for identifying each such bit cell interval as representing the one binary characterization.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |