Fujitsu MHV2060BH User Manual

 

C141-E224 

4-17 

As the servo information, the IDD uses the phase signal servo generated from the 
gray code and servo EVEN and ODD.  This servo information is used for 
positioning operation of radius direction and position detection of circumstance 
direction. 

The servo frame consists of 5 blocks; write/read recovery, servo mark, gray code, 
Burst EVEN1, Burst ODD, Burst EVEN2, and PAD.  Figure 4.8 shows the servo 
frame format. 

 

Write/read  
recovery 

Servo 

mark 

Gray code 

Burst 
EVEN1 

Burst  
ODD 

Burst 
EVEN2 

Post 

code 

(MHV 

2120BH 

only) 

PAD

(1) Write/read recovery 

This area is used to absorb the write/read transient and to stabilize the AGC. 

(2) Servo mark 

This area generates a timing for demodulating the gray code and position-
demodulating the burst signal by detecting the servo mark. 

(3)  Gray code (including sector address bits)  

This area is used as cylinder address.  The data in this area is converted into the 
binary data by the gray code demodulation circuit 

(4)  Burst Even1, Burst Odd, Burst Even2 

These areas are used as position signals between tracks and the IDD control so 
that target phase signal is generated from Burst Even and Burst Odd. 

(5)  Post code (MHV2120BH only) 

This area is used for the precise correction of the servo information which is 
recorded on the media. 

(6) PAD 

This area is used as a gap between servo and data.