Read/Write Circuit; Read/Write Preamplifier (Preamp); Write Circuit; Figure 4.4 Read/Write Circuit Block Diagram - Fujitsu MHV2200BT Product Manual

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.
RDC Block
PreAMP
RDX/RDY
FREF
Register
Address
&DATA
WDX/WDY

Figure 4.4 Read/write circuit block diagram

C141-E244
AGC Ampl Programmable
Amplifier /Asym Filter
Corr. with ADC
TBG/ Timing
SFG Recovery
Ampl/Asym
Corr. Ctl.
AGC
Control
Register
Register
I/O space
Write
PECL
Precomp
Driver
Viterbi Decorder Data
Detector Formatter
Servo Servo
Servo
Sync Sync Mark
Formatter
Peak /Gray Code
Detector Detector
Servo Burst
Demodulator
Precoder
4.6 Read/write Circuit
PERR
NRZ
Interface
Data
[0:8]
Servo Data
[0:2]
SGate
Timer
RGate
WGate
4-9