Patent US3568174A successfully refreshed from Google Patents.
US3568174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compensated readback circuit
Assignee: RCA Corp
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Filing: 1968-03-15
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Granted: 1971-03-02
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Expires: 1988-03-15
Abstract
Abstract In high performance data recording and readback systems, both forward direction and reverse direction reading of the storage medium occurs. The readback signals derived from reading in either direction are phase compensated to make the self-timing clock signal extracted therefrom more accurate.
Inventors
- 👤 George V Jacoby
- 👤 Joseph D Gleitman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:13
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; B; B66; B66C; B66C1/00; B66C1/10; B66C1/12; B66C1/18; G11B9/00; G11B9/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
72 words
In a readback circuit for reading in forward and reverse directions data stored on a polarizable storage medium to obtain forward and reverse readback signals, the combination comprising: first means including a first phase shift circuit coupled to shift the phase of said forward readback signal in one sense; and second means including a second phase shift circuit coupled to shift the phase of said reverse readback signal in the opposite sense.
Claim 2
Dependent Claim
72 words
In a readback circuit for reading in forward and reverse directions data stored on a polarizable storage medium to obtain forward and reverse readback signals, the combination comprising: first means including a first phase shift circuit coupled to shift the phase of said forward readback signal in one sense; and second means including a second phase shift circuit coupled to shift the phase of said reverse readback signal in the opposite sense.
Claim 3
Dependent Claim
27 words
A readback system in accordance with claim 1 wherein said first and second means include first and second phase shift circuits coupled to an amplitude booster network.
Claim 4
Dependent Claim
28 words
A readback systeM in accordance with claim 1 wherein said first and second (means include first and second) phase shift circuits are coupled to an amplitude booster network.
Claim 5
Dependent Claim
38 words
The combination as set forth in claim 3 wherein said resistive circuit elements in said first and second phase shift circuits are effectively connected in parallel with each other to comprise first and second parallel resistive branches respectively.
Claim 6
Dependent Claim
38 words
The combination as set forth in claim 3 wherein said reactive circuit element comprises a single inductor coupled in common to said first and second parallel resistive branches to be common to both of said phase shift circuits.
Claim 7
Dependent Claim
44 words
The combination as set forth in claim 5 that further includes a switching circuit coupled to connect said inductor to said first phase shift circuit for forward readback signals and to connect said inductor to said second phase shift circuit for reverse readback signals.
Claim 8
Dependent Claim
48 words
The combination as set forth in claim 6 wherein said resistive circuit element in said first phase shift circuit is variable and selected to exhibit a high resistance and said resistive circuit element in said second phase shift circuit is variable and selected to exhibit a low resistance.
Claim 9
Dependent Claim
35 words
The combination as set forth in claim 7 that further includes a polarity sensitive amplifier for amplifying said forward and reverse readback signals so that positive and negative polarity alternations thereof exhibit substantially identical amplitudes.
Claim 10
Dependent Claim
99 words
In a readback circuit for reading, in forward and reverse directions, data stored on a polarizable storage medium by transitions in the polarization of said medium, the combination comprising: a transducer coupled to detect said transitions in polarization in said medium to provide forward and reverse readback signals corresponding to reading said forward and reverse directions, respectively; said readback signals exhibiting undesired phase shifts; and bidirectional phase compensation means coupled to said transducer for shifting the phase of said forward readback signals in one direction and for shifting the phase of said reverse readback signals in the opposite direction.
Claim 11
Dependent Claim
99 words
In a readback circuit for reading, in forward and reverse directions, data stored on a polarizable storage medium by transitions in the polarization of said medium, the combination comprising: a transducer coupled to detect said transitions in polarization in said medium to provide forward and reverse readback signals corresponding to reading said forward and reverse directions, respectively; said readback signals exhibiting undesired phase shifts; and bidirectional phase compensation means coupled to said transducer for shifting the phase of said forward readback signals in one direction and for shifting the phase of said reverse readback signals in the opposite direction.
Claim 12
Dependent Claim
60 words
A readback circuit in accordance with claim 9 wherein said bidirectional phase compensation means include first and second phase shift circuits and said readback circuit further includes switching means for coupling said first phase shift circuit to said transducer for said forward readback signals and for coupling said second phase shift circuit to said transducer for said reverse readback signals.
References Cited (Backward Citations)
US2657276A
Cited
US3146430A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |