Fujitsu MHW2040AT - Mobile 40 GB Hard Drive, Product Manual

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4.6 Read/write Circuit
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).
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 output from the hard disk controller (HDC) and sent to the RDC.
The write data is sent to the PreAMP as differential signal, 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
C141-E250 4-9