Fujitsu MHZ2250BJ Manuel d'utilisateur télécharger pdf (Page 66)

Theory of Device Operation

4.6 Read/write Circuit

The read/write circuit consists of the read/write preamplifier (PreAMP), the write

circuit, the read circuit, and the time base generator in the read channel (RDC)

block which is integrated into LSI. Figure 4.4 is a block diagram of the read/write

circuit.

4.6.1 Read/write preamplifier (PreAMP)

PreAMP equips a read preamplifier and a write current switch, that sets the bias

current to the MR device and the current in writing. Each channel is connected to

each data head, and PreAMP switches channel by serial I/O. In the event of any

abnormalities, including a head short-circuit or head open circuit, the write unsafe

signal is generated so that abnormal write does not occur.

4.6.2 Write circuit

The write data is transferred from the hard disk controller (HDC) to the RDC in

LSI. The write data is sent to the PreAMP as differential signal from LSI, and the

data is written onto the media.

(1) Write precompensation

Write precompensation compensates, during a write process, for write non-

linearity generated at reading.

Figure 4.4 Read/write circuit block diagram

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Fujitsu MHZ2250BJ Manuel d'utilisateur Page 66