Table of Contents
Advertisement
8.6.3
Read circuit
After fixing the data output from the head IC to a certain level by Automatic Gain Control (AGC),
the Read circuit converts the waveform digitally by Analog to Digital Converter (ADC) circuit via
analog filter circuit. And then, after equalization by Finite Impulser Response filter (FIR filter),
being converted to logic signal by Viterbi detection circuit, convert into NRZ data by 32/34
decoding circuit, and then the Read circuit sends the data to buffer memory.
(1)
AGC amplifier
The AGC amplifier automatically keeps the output amplitude level constant, even if the input
amplitude level changes. Even if the head output level changes with head characteristics and outer
or inner head position, the AGC amplifier output level is constant.
(2)
Analog filter, ADC, FIR filter and Viterbi detection circuits
AGC amplifier output is demodulated in MEEPRML method as a total process through analog
filter circuit, ADC circuit, FIR filter circuit and Viterbi detection circuit.
(3)
32/34 RLL decoding circuit
The 32/34 RLL decoding circuit decodes the viterbi detection circuit output signal. This decoding
circuit reverse converts (scrambles) the pseudorandom pattern (created at write) into NRZ data.
The NRZ data is then fed to the upper-level circuit.
Table 8.1
MAJ3364 series, MAJ3182 series data frequency and recording density in each zone
Zone
0
0
Cylinder
to
749
1F(MFRPS)
66.2
2F(MFRPS)
264.9
bpi
306,299
Zone
8
7,230
Cylinder
to
8,389
1F(MFRPS)
55.7
2F(MFRPS)
222.8
bpi
346,912
MFRPS: Mega Flux Reversals Per Second
(*1) The value given in parenthesis is for MAJ3182 series.
8 - 8
1
2
750
1,500
to
to
1,499
2,179
66.2
65.5
264.9
262.1
314,109
318,172
9
10
8,390
9,590
to
to
9,589
10,439
53.2
51.7
212.8
206.9
350,784
355,909
C141-E103-01EN
3
4
2,180
2,860
to
to
2,859
4,039
64.6
62.7
258.5
250.8
321,452
325,710
11
12
10,440
11,200
to
to
11,199
12,369
50.2
48.1
200.9
192.4
359,425
367,219
5
6
4,040
5,035
to
to
5,034
6,029
61.4
60.0
245.5
240.0
331,309
337,122
13
14
12,370
13,200
to
to
13,199
13,912
(14,807)*1
46.2
44.7
184.9
178.8
370,280
373,934
(379,601)
7
6,030
to
7,229
57.7
230.9
341,278
15
13,913
to
14,791
42.9
171.5
379,202
Advertisement
Table of Contents
Troubleshooting
