US3684967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic control of position and width of a tracking window in a data recovery system
Assignee: Cogar Corp
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Filing: 1971-01-08
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Granted: 1972-08-15
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Expires: 1991-01-08
Abstract
Abstract A data recovery tracking window for use in phase modulation systems. Each information data pulse triggers a one-shot delay multivibrator. At the trailing edge of the delay pulse, a second one-shot multivibrator generates a window pulse. The window pulse brackets the next data pulse. By keeping the duty cycle of each of the multivibrator waveforms fixed, the window pulses correctly track the data pulses even with a changing data rate. In the preferred embodiment of the invention, a single error detecting circuit is used to keep both duty cycles constant at pre-set values.
Inventors
- 👤 William J Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:54
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1423
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
191 words
A data recovery tracking window generating circuit comprising first means for generating at the output thereof a delay pulse responsive to the presence of each of successive data pulses, each delay pulse being shorter than the interval between two successive data pulses, second means responsive to the termination of each delay pulse for generating at the output thereof a window pulse, each window pulse being shorter than the interval between two successive data pulses and the combined durations of each delay pulse and the following window pulse being longer than the interval between two successive data pulses, each of said delay and window pulse generating means including a control terminal the signal at which controls the duration of the respective generated pulse, means for deriving at least one control signal proportional to the average value of the signal at the output of only one of said pulse generating means, and means for coupling said at least one control signal to the control terminals of said delay and window pulse generating means to maintain the average values of the signals at the outputs of said pulse generating means at respective predetermined values.
Claim 2
Dependent Claim
191 words
A data recovery tracking window generating circuit comprising first means for generating at the output thereof a delay pulse responsive to the presence of each of successive data pulses, each delay pulse being shorter than the interval between two successive data pulses, second means responsive to the termination of each delay pulse for generating at the output thereof a window pulse, each window pulse being shorter than the interval between two successive data pulses and the combined durations of each delay pulse and the following window pulse being longer than the interval between two successive data pulses, each of said delay and window pulse generating means including a control terminal the signal at which controls the duration of the respective generated pulse, means for deriving at least one control signal proportional to the average value of the signal at the output of only one of said pulse generating means, and means for coupling said at least one control signal to the control terminals of said delay and window pulse generating means to maintain the average values of the signals at the outputs of said pulse generating means at respective predetermined values.
Claim 3
Dependent Claim
70 words
A data recovery tracking window generating circuit in accordance with claim 1 further including gate means for extending said data pulses to said first pulse generating means, means for enabling the operation of said gate means responsive to the presence of a window pulse, and means for blocking data pulses from being transmitted to said first pulse generating means until after successive window pulses are synchronized to said data pulses.
Claim 4
Dependent Claim
93 words
A data recovery tracking window generating circuit in accordance with claim 1 wherein each of said first and second pulse generating means is a controlled one-shot multivibrator, and said control signal deriving means includes means for comparing the average value of the signal at the output of one of said first and second pulse generating means to a predetermined value and for developing an error signal proportional to the difference therebetween, and said coupling means couples said error signal to the control terminal of each of said first and second pulse generating means.
Claim 5
Dependent Claim
70 words
A data recovery tracking window generating circuit in accordance with claim 3 further including gate means for extending said data pulses to said first pulse generating means, means for enabling the operation of said gate means responsive to the presence of a window pulse, and means for blocking data pulses from being transmitted to said first pulse generating means until after successive window pulses are synchronized to suCcessive data pulses.
Claim 6
Dependent Claim
71 words
A data recovery tracking window generating circuit in accordance with claim 4 further including means responsive to a predetermined data pulse sequence for operating said blocking means and for applying said predetermined data pulse sequence directly to said first pulse generating means, and means responsive to the termination of said predetermined data pulse sequence for inhibiting the operation of said applying means and for disabling the operation of said blocking means.
Claim 7
Dependent Claim
58 words
A data recovery tracking window generating circuit in accordance with claim 3 wherein said coupling means includes first and second means each connected to a respective one of said control terminals for applying control signals thereto, and means for effecting changes in both of said control signals which are directly proportional to the magnitude of said error signal.
Claim 8
Dependent Claim
64 words
A data recovery tracking window generating circuit in accordance with claim 6 further including means for adjusting said predetermined value to determine the duty cycle of said one of said first and second generating means, and adjustable bias means coupled to the control terminal of the other of said first and second generating means for determining the duty cycle of said other generating means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |