US3736582A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Galloping base line compensating circuit
Assignee: Leach Corp
•
Filing: 1972-03-20
•
Granted: 1973-05-29
•
Expires: 1992-03-20
Abstract
Abstract A compensation circuit that operates to appropriately adjust upward or downward the zero threshold or base line used in recovering digital data recorded in a coded form susceptable to galloping base lines, is disclosed. The compensation circuit operates to detect each transition of the coded signal with respect to the zero threshold. The transitions are further detected to be either an up-going or down-going transition and either early or late with respect to a selected time at which such transition should properly threshold Adjustment of the zero trashold level is made in accordance with the detected characteristics, i.e., up-going or down-going, early or late, of each transition.
Inventors
- 👤 K Norris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:13
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10009; G11B20/10046; G11B20/10203; H; H04; H04L; H04L25/00; H04L25/02; H04L25/06; H04L25/061; H04L25/063; H04L25/065
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
132 words
A compensation circuit for detecting and compensating for any repositioning of the zero threshold of recorded data in the recovery thereof from a recording medium, said recovery of data involving recovered data signals, said compensator circuit including: detector means for detecting the direction of transitions of said recovered data signals through said zero threshold to be either up-going or down-going, a direction signal being provided; aperture means for providing a timing signal that serves to indicate time elapsing between transitions with respect to selected times, the timing signal having a first level preceding said selected times and a second level succeeding said selected times; and gating means, responsive to said direction signal and said timing signal, for providing a correction signal indicative of the direction of said repositioning of said zero threshold.
Claim 2
Dependent Claim
132 words
A compensation circuit for detecting and compensating for any repositioning of the zero threshold of recorded data in the recovery thereof from a recording medium, said recovery of data involving recovered data signals, said compensator circuit including: detector means for detecting the direction of transitions of said recovered data signals through said zero threshold to be either up-going or down-going, a direction signal being provided; aperture means for providing a timing signal that serves to indicate time elapsing between transitions with respect to selected times, the timing signal having a first level preceding said selected times and a second level succeeding said selected times; and gating means, responsive to said direction signal and said timing signal, for providing a correction signal indicative of the direction of said repositioning of said zero threshold.
Claim 3
Dependent Claim
59 words
The circuit defined by claim 1, wherein a reference voltage signal is employed in the recovery of recorded data to detect transitions of said recovered data signal, said compensation circuit further including adjustment means responsive to said correction signal for increasing or decreasing said reference voltage to be modified in a direction opposite said repositioning of said zero threshold.
Claim 4
Dependent Claim
55 words
The circuit defined by claim 1, said detector means including: first means for detecting up-going transitions of said recovered data signals; and second means for detecting down-going transitioNs of said recovered data signals, said direction signal being provided from either said first or second means in response to each transition of said recovered data signal.
Claim 5
Dependent Claim
73 words
The circuit defined by claim 1, said aperture means including: timing signal means for providing a pulsed signal having a first level or a second level in response to being set or reset, respectively; and means for setting said timing signal means at said selected times to provide a change of levels for said pulsed signal at said selected times, said timing signal means being reset a predetermined period after said selected times.
Claim 6
Dependent Claim
72 words
The circuit defined by claim 4, said timing means including a bistable device adapted to change states in response to signals applied to set and reset terminals thereof, said means for setting said timing signal means including a counter having output terminals connected to provide signals to set said bistable device at said selected times, said counter having terminals connected to reset said bistable device a predetermined period after said selected times.
Claim 7
Dependent Claim
63 words
The circuit defined by claim 1, said gating means including a plurality of AND gates connected to receive a direction signal from said detector means, a particular one of said AND gates providing an output responsive to coincidently receiving said timing signal, the output of said AND gate forming said correction signal and indicating the direction of said repositioning of said zero threshold.
Claim 8
Dependent Claim
59 words
The circuit defined by claim 2, said adjustment means including an up/down counter connected to receive said correction signal, the contents of said up/down counter being incremented upward as dictated by said correction signal when applied to an up command terminal or incremented downward by said correction signal when applied to a down command terminal of said up/down counter.
Claim 9
Dependent Claim
73 words
The circuit defined by claim 3, said aperture means including: timing signal means for providing a pulsed signal having a first level or a second level in response to being set or reset, respectively; and means for setting said timing signal means at said selected times to provide a change of levels for said pulsed signal at said selected times, said timing signal means being reset a predetermined period after said selected times.
Claim 10
Dependent Claim
62 words
The circuit defined by claim 8,said gating means including a plurality of AND gates connected to receive a direction signal from said detector means, a particular one of said AND gates providing an output responsive to coincidentally receiving said timing signal, the output of said AND gate forming said correction signal and indicating the direction of said repositioning of said zero threshold.
Claim 11
Dependent Claim
59 words
The circuit defined by claim 9, wherein a reference voltage signal is employed in the recovery of recorded data to detect transitions of said recovered data signal, said compensation circuit further including adjustment means responsive to said correction signal for increasing or decreasing said reference voltage to be modified in a direction opposite said repositioning of said zero threshold.
Claim 12
Dependent Claim
59 words
The circuit defined by claim 10, said adjustment means including an up/down counter connected to receive said correction signal, the contents of said up/down counter being incremented upward as dictated by said correction signal when applied to an up command terminal or incremented downward by said correction signal being applied to a down command terminal of said up/down counter.
Claim 13
Dependent Claim
72 words
The circuit defined by claim 11, said timing means including a bistable device adapted to change states in response to signals applied to set and reset terminals thereof, said means for setting said timing signal means including a counter having output terminals connected to provide signals to set said bistable device at said selected times, said counter having terminals connected to reset said bistable device a predetermined period after said selected times.
Claim 14
Dependent Claim
104 words
A compensation circuit foR adjusting the zero threshold reference voltage used by playback circuitry for detecting the transitions of a recovered data signal through a zero threshold level, the compensation circuit including: means for determining the characteristics of each said transitions to be either up-going or down-going and either early or late with respect to selected times, a transition characteristic signal being provided indicative of the repositioning of said zero threshold from an initial level; and control means responsive to said transition characteristic signal for adjusting said zero threshold reference voltage to compensate for said repositioning of said zero threshold from an initial level.
Claim 15
Dependent Claim
104 words
A compensation circuit foR adjusting the zero threshold reference voltage used by playback circuitry for detecting the transitions of a recovered data signal through a zero threshold level, the compensation circuit including: means for determining the characteristics of each said transitions to be either up-going or down-going and either early or late with respect to selected times, a transition characteristic signal being provided indicative of the repositioning of said zero threshold from an initial level; and control means responsive to said transition characteristic signal for adjusting said zero threshold reference voltage to compensate for said repositioning of said zero threshold from an initial level.
Claim 16
Dependent Claim
76 words
The circuit defined by claim 13, said means for detecting the characteristics of each said transitions including: first means for detecting said transitions to be up-going or down-going, a corresponding direction signal being provided; second means for providing an early/late timing signal having an early level preceding said selected time and a late level suceeding said selected times; and third means responsive to said direction signal and said early/late signal for providing said transition characteristic signal.
Claim 17
Dependent Claim
25 words
The circuit defined by claim 14, said first means including: a first detector for detecting up-going transitions; and a second detector for detecting down-going transitions.
Claim 18
Dependent Claim
79 words
The circuit defined by claim 15, said second means including: a bistable device adapted to be set and reset in response to signals applied to set and reset terminals thereof,said early/late signal being provided at an output terminal of said bistable device; and a counter connected to set and reset said bistable device at certain counts corresponding to said selected times, the counter being connected to be initialized in response to signals applied from said first or second detectors.
Claim 19
Dependent Claim
54 words
The circuit defined by claim 16, said third means including a plurality of AND gates selectively connected to said first and second detectors and to said bistable device to have a single one of said AND gates enabled for each transition, the enabled AND gate providing a transition characteristic signal to said control means.
Claim 20
Dependent Claim
67 words
The circuit defined by claim 17, the control means including an up/down counter having an up command input terminal and a down command input terminal which are respectively connected to selected ones of said AND gates, said up/down counter being incremented in response to a transition characteristic signal from an AND gate and in a direction corresponding to a required adjustment of said zero threshold reference voltage.
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) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |