Writing Pulse Waveform Of Dvd+R - LG GSA-4120B Service Manual

4. Writing Pulse Wave Form of DVD+R
For different speed ranges, different write strategies can be used. This document specifies 2 options:
- a pulsed write strategy, where each single mark is created by a number of subsequent separated short
pulses.
- a blocked write strategy, where each single mark is created by one continuous pulse.
1) 1 st Method : Using Pulsed Write Strategy
* 3T :
NRZI
Channel bits
P
p
P
b
N = 3 : only the top pulse(T
first pulse lead-time dT
* > 4T :
NRZI
Channel bits
P
p
P
b
N > 4 : the top pulse (T
first pulse lead-time dT
Pp : Actual write power
Pb : Bias Power
T = 3
2Tw
T
top
dT
top
dT
le
T > 4
2Tw
T
top
dT
top
dT
le
),
top
, dT
top le
Tw
T
mp
T
mp
), multi-pulse (T
top
, dT
le
top
T
lp
) and last pulse (T ),
mp
lp
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