Patent US4580176A successfully refreshed from Google Patents.
US4580176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive equalization circuit for magnetic recording channels utilizing signal timing
Assignee: International Business Machines Corp
•
Filing: 1983-11-21
•
Granted: 1986-04-01
•
Expires: 2003-11-21
Abstract
Abstract An adaptive equalization circuit for magnetic recording channels which derives an error signal to change the equalizer compensation value from the timing of random signal data and provides continuous feedback compensation.
Inventors
- 👤 David C. Graves
- 👤 Richard C. Schneider
- 👤 Volker Zimmermann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:38
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10009; G11B20/10046; G11B5/00; G11B5/02; G11B5/027; G11B5/035
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
154 words
An equalization circuit for a magnetic recording data channel which utilizes a feedback compensation path to provide a correction signal to one input of a summation amplifier, which functions as an element of a variable equalizer, wherein the amplifier receives a magnetic recording signal as its other input and provides a compensation signal as the output of the summation amplifier; timing sensing means for sensing the relative timing of random data pulses of the data channel and providing an output signal as an indication of error, logic circuit means receiving the timing sensing means output signal and providing an output in response thereto for interpreting whether the timing is equivalent to an over compensated or an under compensated state, and circuit means providing the output of the logic circuit means as the correction signal input to vary the compensation signal provided by the summation amplifier in the feedback compensation path of the equalization circuit.
Claim 2
Dependent Claim
154 words
An equalization circuit for a magnetic recording data channel which utilizes a feedback compensation path to provide a correction signal to one input of a summation amplifier, which functions as an element of a variable equalizer, wherein the amplifier receives a magnetic recording signal as its other input and provides a compensation signal as the output of the summation amplifier; timing sensing means for sensing the relative timing of random data pulses of the data channel and providing an output signal as an indication of error, logic circuit means receiving the timing sensing means output signal and providing an output in response thereto for interpreting whether the timing is equivalent to an over compensated or an under compensated state, and circuit means providing the output of the logic circuit means as the correction signal input to vary the compensation signal provided by the summation amplifier in the feedback compensation path of the equalization circuit.
Claim 3
Dependent Claim
22 words
The equalization circuit of claim 1 wherein the feedback compensation path operates continually on random date pulses of the magnetic recording signal.
Claim 4
Dependent Claim
15 words
The equalization circuit of claim 2 further including a fixed equalizer in the data channel.
Claim 5
Dependent Claim
20 words
The equalization circuit of claim 3 wherein the timing sensing means comprises means for detecting three relative levels of timing.
Claim 6
Dependent Claim
21 words
The circuit of claim 4 wherein the means provided to receive the output of the logic circuit means includes charge pump.
Claim 7
Dependent Claim
106 words
An adaptive equalization circuit for a magnetic recording channel comprising: recording channel sensing and amplification means, means for sensing and determining data 1's and data 0's on the channel, time detection means for continuously monitoring the relative timing of random data pulses on the channel and producing timing signals therefor, logic means receiving the timing signals for determining the instantaneous compensation state of the data pulses for which timing is sensed, signal means receiving the output of the logic means for providing a control signal, and variable equalizer means for continuously varying the equalization of the channel in response to the output of the signal means.
Claim 8
Dependent Claim
106 words
An adaptive equalization circuit for a magnetic recording channel comprising: recording channel sensing and amplification means, means for sensing and determining data 1's and data 0's on the channel, time detection means for continuously monitoring the relative timing of random data pulses on the channel and producing timing signals therefor, logic means receiving the timing signals for determining the instantaneous compensation state of the data pulses for which timing is sensed, signal means receiving the output of the logic means for providing a control signal, and variable equalizer means for continuously varying the equalization of the channel in response to the output of the signal means.
Claim 9
Dependent Claim
13 words
The circuit of claim 6 where the equalization means comprises a variable amplifier.
Claim 10
Dependent Claim
21 words
The circuit of claim 7 wherein the signal means comprises charge pump means for receiving the output of the logic means.
Claim 11
Dependent Claim
20 words
The circuit of claim 7 wherein the adaptive equalization circuit further includes a fixed equalizer in the recording channel path.
Claim 12
Dependent Claim
21 words
The circuit of claim 8 wherein the logic means is responsive to left shift and right shift of instantaneous data position.
References Cited (Backward Citations)
US3792356A
Cited
US3827078A
Cited
US3868603A
Cited
US3898564A
Cited
US4005477A
Cited
SU587621A2
Cited
US4157573A
Cited
SU669387A2
Cited
JPS55105815A
Cited
US4367495A
Cited
US4296445A
Cited
US4361892A
Cited
US4512005A
Cited
US4422175A
Cited
US4495531A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-31 | 1989-09-30 | 1990-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-31 | 1993-09-30 | 1994-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-31 | 1997-09-30 | 1998-04-01 | $7700.00 | Window Closed / Lapsed |