Dynamic magnetic information storage or retrieval – General recording or reproducing – Specifics of biasing or erasing
Reexamination Certificate
2005-03-15
2005-03-15
Hudspeth, David (Department: 2657)
Dynamic magnetic information storage or retrieval
General recording or reproducing
Specifics of biasing or erasing
C360S046000, C360S067000
Reexamination Certificate
active
06867941
ABSTRACT:
A circuit controls the gain of an amplifier that amplifies an information signal. The circuit includes a buffer for storing first and second samples of the amplified information signal, and a gain-determination circuit coupled to the buffer. The gain-determination circuit generates a gain adjustment based on the sum of the first and second samples, the gain adjustment causing the amplifier to change the amplitude of the amplified information signal to or toward a predetermined amplitude. Such a circuit can provide an initial, coarse gain adjustment to a read-signal amplifier in a disk-drive read channel. Compared to prior read channels, this initial adjustment promotes faster settling of the amplifier gain at the beginning of a data sector. This faster settling allows the data sector to have a shorter preamble, and thus allows the disk to have a higher data-storage density. Furthermore, because the phase angle between the sample clock and the preamble sinusoid may be unknown at the beginning of the data sector, the circuit can determine the initial gain adjustment independent of this phase angle.
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Colon Rocio
Hudspeth David
Jorgenson Lisa K.
Santarelli Bryan A.
STMicroelectronics Inc.
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