LG 7823W, Service Manual

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To make recordings, it is necessary to modulate the write pulse, which is called “Write Strategy”.
There can be many types in Write Strategy. Typically Write Strategy for DVD ±R has NMP(Non Multi-Pulse) type and
MP(Multi-Pulse) type. In NMP type each single mark is created by subsequent separated short pulses. In MP type each
single mark is created by one continuous pulse.
Write Strategy for DVD ±RW has Type 1 and Type2. In Type 1 the mark with nT width is created by one top pulse and (n-2)
multi-pulses. Thus mark 3T is made by one top pulse and one multi-pulse. In Type 2 the mark with nT width is created by
one top pulse and (n-3) multi-pulses. Thus mark 3T is made by one top pulse only.
RL-02A uses MP type Write Strategy for DVD ±R and Type 1 for DVD ±RW as shown below.
Po :Write Power (Peak Power)
Pe :Erase Power
Pb :Bias Power
Recording data
Twd (3T )
Twd ( 8T )
Ttop
Tmp
Po
Ttop
Zero Level
Pb
Write pulse
for DVD R
Ttop
Ttop
Tmp
Po
Pb
Pe
Write pulse
for DVD RW
Tmp
Zero Level
Tcl Tcl