Table of Contents
Advertisement
PR-8210-A
Tracking
Eror
Mirror rotat.on
|
Center point
Following track
Stoope* contact
L
ол.
са
OL
us
Xs
es
%;
opens
= returns 10
ти
center pos: tion
Fig. 15 Tracking mirror
operation during scan mode
20
servo mechanisms being switched to "open loop".
Тһе jump-back
pulse output
signal from
pin 1 is
differentiated.
level-adjusted.
by УВВ,
and
then
applied to AMP2.
The laser beam traverses the tracks as indicated
in the time chart Fig. 16 and moves
to an inter-
mediate
point
between
one
track
and
the next.
When
the tracking error intersects the zero cross-
point in the positive direction, the pin 1 jump-back
pulse output returns to OV resulting in the tracking
loop being closed,
and the differentiated
DC vol-
tage being applied to the AMP2 input in a direction
which
will suppress the inertial movement
of the
mirror.
PN
16
JUMP BACK TRIG iN
Lf
PIN 1
JUMPBACK OUT
PIN 4
|
AMP 2IN
PIN 27
14045
TRKG ERROR IN
џ
2
А
~
>
۲
`
BEAM SPOTS
ON THE DISC
о
'
+
+
4
TRACK
А
А
Ac
А-1
Fig. 16 Jump back operation timing chart
Advertisement
Table of Contents
