Patent AT112443B successfully refreshed from Google Patents.
US3662364A
Expired / Lapsed
US
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Scan control for synchronizing a data signal with a clock signal
Assignee: International Business Machines Corp
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Filing: 1969-12-22
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Granted: 1972-05-09
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Expires: 1989-12-22
Abstract
Abstract A magneto-optic transducing system is utilized to convert a magnetic recording into electrical signals. For purposes of decoding the electrical signals into data, it is necessary that the electrical signal transduced from a magnetic recording be synchronized with a reference clock signal. Synchronization is obtained herein by fixing the frequency of the reference clock signal and varying the frequency of the data signal as transduced from the magnetic recording. The frequency and phase of the data signal are varied by varying the scanning sweep speed used in a magneto-optic transducer. Two alternative embodiments are shown. In the first embodiment, the scanning is accomplished by a vidicon which scans the magneto-optic image of a large block of data. In an alternative embodiment, a cathode ray tube is used as the light source for the magneto-optic transducer so that each bit may be separately scanned by deflecting the beam in the cathode ray tube. Synchronization is obtained by comparing the frequency and phase of the data signal from the transducing system with the frequency and phase of the reference clock and feeding back an error signal to the deflection coils of the cathode ray tube or the vidicon. The correction signal increases or decreases the sweep speed as is necessary to synchronize the data with the clock.
Inventors
- 👤 Arvindkumar M Patel
- 👤 Anton G Wellbrock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:02
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
119 words
Apparatus for synchronizing an information signal read from a magnetic recording on a magnetic storage medium with a clock having a relatively fixed frequency comprising: scanning means for scanning the magnetic recording to read out the information signal, the sweep speed of said scanning means being adjustable so that the frequency and phase of the information signal read out is adjustable; means for comparing the frequency and phase of the information signal with the relatively fixed frequency and phase of the clock signal; means responsive to said comparing means for adjusting the sweep speed of said scanning means until the frequency and phase of the information signal is the same as the frequency and phase of the clock signal.
Claim 2
Dependent Claim
119 words
Apparatus for synchronizing an information signal read from a magnetic recording on a magnetic storage medium with a clock having a relatively fixed frequency comprising: scanning means for scanning the magnetic recording to read out the information signal, the sweep speed of said scanning means being adjustable so that the frequency and phase of the information signal read out is adjustable; means for comparing the frequency and phase of the information signal with the relatively fixed frequency and phase of the clock signal; means responsive to said comparing means for adjusting the sweep speed of said scanning means until the frequency and phase of the information signal is the same as the frequency and phase of the clock signal.
Claim 3
Dependent Claim
53 words
Apparatus of claim 1 wherein said scanning means comprises: a magneto-optic transducer for converting variations in the magnetic recording into variations in radiant energy; means for sweeping said transducer with a beam to generate the information signal from the variations in the radiant energy, the sweep speed of said sweeping means being adjustable.
Claim 4
Dependent Claim
76 words
Apparatus of claim 2 wherein said sweeping means comprises: an image screen; means for projecting the variations in radiant energy onto the image screen; an electron beam scanner for scanning the image screen; means for converting the electron beam striking the image screen into the information signal indicative of the radiant energy variations; means for changing the sweep speed of said electron beam scanner so that the frequency and phase of the information signal is adjustable.
Claim 5
Dependent Claim
109 words
Apparatus of claim 2 wherein said sweeping means comprises: a cathode ray tube for generating a spot of light that sweeps across the face of the tube as the cathode ray beam is deflected; means for focussing the spot of light from said cathode ray tube onto said magneto-optic transducer so that variations in the magnetic recording are converted into variations in radiant energy as the spot of light sweeps across said transducer; means for converting the variations in radiant energy into the information signal; means for changing the rate of deflection of said cathode ray beam so that the frequency and phase of the information signal is adjustable.
Claim 6
Dependent Claim
71 words
Method for synchronizing data read from a magnetic storage medium with a clock having a substantially fixed frequency comprising the steps of: magneto-opTically scanning the recording on the magnetic storage medium to read out the data; comparing transitions in the data, magneto-optically read out, with clock transitions from the fixed frequency clock; varying the sweep speed of said scanning step until the data transitions and the clock transitions are substantially concurrent.
Claim 7
Dependent Claim
71 words
Method for synchronizing data read from a magnetic storage medium with a clock having a substantially fixed frequency comprising the steps of: magneto-opTically scanning the recording on the magnetic storage medium to read out the data; comparing transitions in the data, magneto-optically read out, with clock transitions from the fixed frequency clock; varying the sweep speed of said scanning step until the data transitions and the clock transitions are substantially concurrent.
Claim 8
Dependent Claim
57 words
Method of claim 5 wherein the step of magneto-optically scanning comprises the steps of: magneto-optically transforming the recording into variations in a radiant energy beam to read out the data; sweeping the radiant energy beam while magneto-optically transforming the recording whereby the time of occurrence of data transitions, magneto-optically read out, is dependent on the sweep speed.
Claim 9
Dependent Claim
58 words
Method of claim 6 wherein the step of sweeping comprises the steps of: projecting the variations in the radiant energy beam onto an image screen; scanning the image screen with an electron beam, the sweep speed of the electron beam during scanning being variable so that the time of occurrence of data transitions, magneto-optically read out, is variable.
Claim 10
Dependent Claim
150 words
In a magneto-optic transducing system for converting a magnetic recording into variations in radiant energy and, thereafter, into variations in electrical signals, apparatus for synchronizing the electrical signal carrying the recorded information with a clock signal having a fixed predetermined frequency, comprising: means for changing the rate at which the magnetic recording is transduced magneto-optically into an electrical signal; means for comparing the electrical signal with the clock signal and generating an error signal indicative of the lack of synchronization between the clock signal and the electrical signal carrying the recorded information; said changing means responsive to the error signal to change the rate at which the magnetic recording is magneto-optically transduced, the magnitude and sign of the change being dependent on the error signal so that the rate of transducing the information will be changed until the electrical signal carrying the recorded information is synchronized with the clock signal.
Claim 11
Dependent Claim
150 words
In a magneto-optic transducing system for converting a magnetic recording into variations in radiant energy and, thereafter, into variations in electrical signals, apparatus for synchronizing the electrical signal carrying the recorded information with a clock signal having a fixed predetermined frequency, comprising: means for changing the rate at which the magnetic recording is transduced magneto-optically into an electrical signal; means for comparing the electrical signal with the clock signal and generating an error signal indicative of the lack of synchronization between the clock signal and the electrical signal carrying the recorded information; said changing means responsive to the error signal to change the rate at which the magnetic recording is magneto-optically transduced, the magnitude and sign of the change being dependent on the error signal so that the rate of transducing the information will be changed until the electrical signal carrying the recorded information is synchronized with the clock signal.
Claim 12
Dependent Claim
98 words
In a magneto-optic transducing system, the apparatus of claim 8 wherein said changing means comprises: a cathode ray tube having a screen; means for projecting the variations in the radiant energy onto the screen; deflection coils for the cathode ray for scanning the cathode ray across the screen; a correction deflection coil for the cathode ray responsive to the error signal to deflect the ray in addition to the normal deflection due to the other deflection coils so that the sweep speed of the cathode ray during the scanning of the screen is dependent upon the error signal.
Claim 13
Dependent Claim
81 words
In a magneto-optic transducing system, the apparatus of claim 8 wherein said changing means comprises: a flying spot scanner for generating the radiant energy beam used in the magneto-optic transducing system; means for altering the sweep speed of said flying spot in response to the error signal so that the sweep speed of the radiant energy beam is dependent upon the error signal, and, therefore, the rate at which the magnetic recording is magneto-optically transduced is dependent upon the error signal.
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) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |