US4222080A
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Velocity tolerant decoding technique
Assignee: International Business Machines Corp
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Filing: 1978-12-21
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Granted: 1980-09-09
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Expires: 1998-12-21
Abstract
Abstract A decoding technique applicable to binary data encoded by phase encoding (PE), frequency modulation (FM), or modified frequency modulation (MFM). Resynchronization of the decoding clocking circuitry occurs upon every flux transition, rather than at less than all flux transitions, such as only at each data flux transition in the case of phase encoding. The technique provides substantially greater velocity tolerance than previous techniques for decoding codes encoded in this manner.
Inventors
- 👤 Giles R. Frazier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:52
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1423; G11B20/1407; G11B20/1419
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
137 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions sebsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions.
Claim 2
Independent Claim
137 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions sebsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions.
Claim 3
Independent Claim
114 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and generating signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two consecutive ones of said first pulse and the absence of any of said signal transitions intervening between said first pulse signals.
Claim 4
Independent Claim
114 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and generating signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two consecutive ones of said first pulse and the absence of any of said signal transitions intervening between said first pulse signals.
Claim 5
Independent Claim
107 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two of said first pulses separated by an even number of said signal transitions.
Claim 6
Independent Claim
107 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two of said first pulses separated by an even number of said signal transitions.
Claim 7
Independent Claim
213 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions subsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions; generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two consecutive ones of said first pulse and the absence of any of said signal transitions intervening between said first pulse signals; and generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two of said first pulses separated by an even number of said signal transitions.
Claim 8
Independent Claim
213 words
A method of detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions subsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions; generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two consecutive ones of said first pulse and the absence of any of said signal transitions intervening between said first pulse signals; and generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two of said first pulses separated by an even number of said signal transitions.
Claim 9
Dependent Claim
53 words
The method of claim 1, or 2, or 3 wherein said step of generating said first pulse further comprises: comparing the time period between two consecutive signal transitions to a referenced time; and generating said first pulse when said time period between signal transitions is equal to or greater than said reference time.
Claim 10
Dependent Claim
132 words
The method of claim 1, or 2, or 3, wherein said step of generating said first pulse further comprises: comparing the time period between two consecutive signal transitions to the time period between the first of said two consecutive signal transitions and the signal transition immediately preceding said first of said two consecutive signal transitions; and generating said first pulse when said time period between said two consecutive signal transitions is at least three-halves the time period between said first of said two consecutive signal transitions and said signal transition immediately preceding said first of said two consecutive signal transitions when said time period between said first of said two consecutive signal transitions and said signal transition immediately preceding said first of said two consecutive signal transitions is a short time duration.
Claim 11
Independent Claim
143 words
A system for detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions subsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions.
Claim 12
Independent Claim
143 words
A system for detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; and means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions subsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions.
Claim 13
Independent Claim
223 words
A system for detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions subsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions; means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two consecutive ones of said first pulse and the absence of any of said signal transitions intervening between said first pulse signals; and means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two of said first pulses separated by an even number of said signal transitions.
Claim 14
Independent Claim
223 words
A system for detecting data transitions or clock transitions in a sequence of signal transitions representing data encoded by phase encoding or frequency modulation, respectively, wherein the time duration between any two consecutive signal transitions is characterized as either long or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of an even number of signal transitions subsequent to the previous data transition or clock transition, respectively, and the absence of said first pulse during the time between said previous data transition or clock transition and the last of said even number of signal transitions; means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two consecutive ones of said first pulse and the absence of any of said signal transitions intervening between said first pulse signals; and means for generating a signal indicative of the detection of a data transition or clock transition, respectively, responsive to the occurrence of two of said first pulses separated by an even number of said signal transitions.
Claim 15
Independent Claim
157 words
A method of deriving signals for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a second plate responsive only to each detection of a middle time duration between two of said signal transitions; generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; and generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse.
Claim 16
Independent Claim
157 words
A method of deriving signals for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a second plate responsive only to each detection of a middle time duration between two of said signal transitions; generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; and generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse.
Claim 17
Independent Claim
180 words
A method of decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse; and outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal.
Claim 18
Independent Claim
180 words
A method of decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse; and outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal.
Claim 19
Dependent Claim
26 words
The method of claim 10 further comprising: outputting a zero responsive to said third signal when said pulse following said third signal is a second pulse.
Claim 20
Dependent Claim
30 words
The method of claim 10 further comprising: outputting a zero followed by a one responsive to said third signal when said pulse following said third signal is a first pulse.
Claim 21
Dependent Claim
33 words
The method of claim 10 further comprising: outputting a zero responsive to said fourth signal when said signal transition following said fourth signal occurs in said short time duration after said fourth signal.
Claim 22
Dependent Claim
30 words
The method of claim 10 further comprising: outputting a zero followed by a one responsive to said fourth signal when said pulse following said fourth signal is a second pulse.
Claim 23
Dependent Claim
27 words
The method of claim 10 further comprising: outputting an intercharacter mark responsive to said fourth signal when said pulse following said fourth signal is a first pulse.
Claim 24
Independent Claim
271 words
A method of decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse; outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal; outputting a zero responsive to said third signal when said pulse following said third signal is a second pulse; outputting a zero followed by a one responsive to said third signal when said pulse following said third signal is a first pulse; outputting a zero responsive to said fourth signal when said signal transition following said fourth signal occurs in said short time duration after said fourth signal; and outputting a zero followed by a one responsive to said fourth signal when said pulse following said fourth signal is a second pulse.
Claim 25
Independent Claim
271 words
A method of decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: detecting the occurrence of each of said signal transitions; generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse; outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal; outputting a zero responsive to said third signal when said pulse following said third signal is a second pulse; outputting a zero followed by a one responsive to said third signal when said pulse following said third signal is a first pulse; outputting a zero responsive to said fourth signal when said signal transition following said fourth signal occurs in said short time duration after said fourth signal; and outputting a zero followed by a one responsive to said fourth signal when said pulse following said fourth signal is a second pulse.
Claim 26
Independent Claim
167 words
A system for deriving signals for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; means for generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; and means for generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse.
Claim 27
Independent Claim
167 words
A system for deriving signals for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; means for generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; and means for generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second pulses having occurred since the last first pulse.
Claim 28
Independent Claim
154 words
A system for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; means for generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; means for outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal.
Claim 29
Independent Claim
154 words
A system for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; means for generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; means for outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal.
Claim 30
Independent Claim
290 words
A system for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; means for generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; means for generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second having occurred since the last first pulse; means for outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal; means for outputting a zero responsive to said third signal when said pulse following said third signal is a second pulse; means for outputting a zero followed by a one responsive to said third signal when said pulse following said third signal is a first pulse; means for outputting a zero responsive to said fourth signal when said signal transition following said fourth signal occurs in said short time duration after said fourth signal; and means for outputting a zero followed by a one responsive to said fourth signal when said pulse following said fourth signal is a second pulse.
Claim 31
Independent Claim
290 words
A system for decoding binary data from a sequence of signal transitions representing said data encoded by modified frequency modulation encoding, wherein the time duration between any two consecutive signal transitions is characterized as either long, middle, or short, comprising: means for detecting the occurrence of each of said signal transitions; means for generating a first pulse responsive only to each detection of a long time duration between two of said signal transitions; means for generating a second pulse responsive only to each detection of a middle time duration between two of said signal transitions; means for generating a third signal indicative of the detection of the occurrence of a signal transition with an even number of second pulses having occurred since the last first pulse; means for generating a fourth signal responsive to the occurrence of a short time duration between signal transitions or said second pulse, with an odd number of said second having occurred since the last first pulse; means for outputting a one responsive to said third signal when the signal transition following said third signal occurs in said short time duration after said third signal; means for outputting a zero responsive to said third signal when said pulse following said third signal is a second pulse; means for outputting a zero followed by a one responsive to said third signal when said pulse following said third signal is a first pulse; means for outputting a zero responsive to said fourth signal when said signal transition following said fourth signal occurs in said short time duration after said fourth signal; and means for outputting a zero followed by a one responsive to said fourth signal when said pulse following said fourth signal is a second pulse.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1983-09-09 | 1984-03-10 | 1984-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-09 | 1988-03-10 | 1988-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-09 | 1992-03-10 | 1992-09-09 | $7700.00 | Window Closed / Lapsed |