Dynamic magnetic information storage or retrieval – General processing of a digital signal – Head amplifier circuit
Patent
1997-05-21
1999-10-12
Faber, Alan
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Head amplifier circuit
360 67, G11B 509
Patent
active
059662581
ABSTRACT:
A sampled amplitude read channel is disclosed for reading data recorded on a disk storage medium by detecting an estimated binary sequence from a sequence of discrete-time sample values generated by sampling pulses in an analog read signal from a read head positioned over the disk storage medium. The read channel comprises a variable gain amplifier for adjusting the magnitude of the analog read signal before sampling, and a discrete-time gain control loop for generating a gain control signal applied to the VGA in response to the discrete-time sample values. The discrete-time sample values may, or may not be, synchronized to a baud rate of the recorded data. For example, when reading the user data the discrete-time sample values are synchronous, and when reading a servo address mark (SAM) the sample values are asynchronous. As such, the discrete-time gain control loop of the present invention is programmable to operate in a synchronous or asynchronous mode. In asynchronous mode, the gain error is computed in a manner that is less sensitive to amplitude fluctuations over long blocks of data. This is accomplished by computing the gain error as the difference between a predetermined set point and the maximum absolute sample value over a programmable block length.
REFERENCES:
patent: 5089757 (1992-02-01), Wilson
patent: 5231545 (1993-07-01), Gold
patent: 5258933 (1993-11-01), Johnson et al.
patent: 5260976 (1993-11-01), Dolivo et al.
patent: 5297184 (1994-03-01), Behrens et al.
patent: 5311178 (1994-05-01), Pan et al.
patent: 5329251 (1994-07-01), Llewellyn
patent: 5341249 (1994-08-01), Abbott et al.
patent: 5345342 (1994-09-01), Abbott et al.
patent: 5359631 (1994-10-01), Behrens et al.
patent: 5375145 (1994-12-01), Abbott et al.
patent: 5384671 (1995-01-01), Fisher
patent: 5406427 (1995-04-01), Shimoda
patent: 5420893 (1995-05-01), Ward
patent: 5424881 (1995-06-01), Behrens et al.
patent: 5438460 (1995-08-01), Coker et al.
patent: 5448424 (1995-09-01), Hirano et al.
patent: 5448571 (1995-09-01), Hong et al.
patent: 5459769 (1995-10-01), Ziperovich
patent: 5502408 (1996-03-01), Scholz
patent: 5668678 (1997-09-01), Reed et al.
John Vanderkooy and Stanley P. Lipschitz, "Resolution Below the Least Significant Bit in Digital Systems with Dither," J. Audio Eng. Soc., vol. 32, No. 3, Mar. 1984.
Edward A. Lee and David G. Messerschmitt, "Timing Recovery," Digital Communications, Chapter 15, pp. 560-585, Kuwer Academic Publishers, Boston, 1988.
Cideciyan et al., "A PRML System for Digital Magnetic Recording," IEEE Journal on Selected Areas in Communications, vol. 10, No. 1, Jan. 1992.
Cirrus Logic Inc.
Faber Alan
Sheerin Howard H.
Shifrin Dan A.
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