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Philips 22RC026/00 - Functional Explanation; APC (Auto laser power control); RF Amplifier; SLC (Slice level control)

Philips 22RC026/00
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FUNCTIONAL
EXPLANATION
:
FUNTIONAL
EXPLANATION
1.
APC
(Auto
laser
power
control)
5.
Tracking
servo
This
is
the
circuit
to
control
laser
power
of
pickup,
and
laser
ON/OFF
is
set
by
command
from
micro
computer.
.
RF
Amplifier
(|
pattern
output)
This
inputs
pickup
photo
diode
output
current
(A+C)
to
FIN2
(ipin),
and
(B+D)
to
FIN1
(2pin).
Input
current
is
IV-converted,
and
output
to
RFSM
(41pin)
of
RFSM
amplifier
output
by.
way
of
AGC
circuit.
Self-contained
AGC
circuit
has
variable
range
of
+3dB,
and
the
time
constant
can
be
varied
by
outside-fixed
condenser
of
PH1
(60pin).
This
also
controls
bottom
level
of
EFM
signal
(RFSM
output),
and
this
response
can
be
varied
by
outside-fixed
condenser
of
BH1
(61pin).
Central
gain
of
AGC
variable
range
is
set
by
resistance
value
between
RFSM
(41pin)
and
RFS-(42pin).
.
SLC
(Slice
level
control)
SLC
makes
duty
of
EFM
signa!
which
is
input
to
DSP
50%.
This
judges
duty,
and
decides
DC
level
by
inte-
grating
EFMO
signal
which
is
output
from
DSP.
.
Focus
servo
Focus
error
signal
can
be
gained
by
detecting
the
dif-
ference
between
(A+C)
and
(B+D),
which
is
(B+D)-
(A+C),
and
it
is
sent
to
FE
(20pin).
Focus
error
signal
gain
is
set
by
resistance
value
between
FE
(20pin)
and
FE-(21pin).
FA
amplifier
is.
phase
compensating
Amplifier,
and
the
equalizer
curve
is
set
by
outside-fixed
condenser
and
resistance.
Besides,
this
amplifier
has
muting
function.
FD
amplifier
has
the
following
functions;
phase
com-
pensating
circuit,
focus
search
signal
synthesis,
and
offset
cancelling.
Focus
search
starts
by
F-SERCH
command,
and
generates
lamp
waveshape
by
inner
clock.
Focus
error
signal
by
this
waveshape
detects
in-
focus
condition
(focus
zero
cross),
and
turns
on
focus
servo.
Lamp
waveshape
amplitude
is
set
by
resistance
between
FD
(16pin)
and
FD-(17pin).
This
inputs
pickup
photo
diode
output
current
to
E
(Spin)
and
F
(4pin).
input
current
is
|V-converted,
and
output
to
TE
(7pin)
by
way
of
VCA
circuit
for
balance
adjustment
and
VCA
circuit
for
follow-up
to
RFAGC
cir-
cuit.
Tracking
error
gain
is
set
by
resistance
between
TE-(6pin)
and
TE
(7pin).
;
TOFF
amplifier
just
after
TE
(7pin)
turns
off
servo
b
TOFF
signal
from
DSP.
|
TH
amplifier
varies
servo
response
characteristic
by
TGL
signal
from
DSP.
or
by
THLD
signal
of
inside
for-
mation
by
detecting
JP
signal.
When
DEFECT
is
de-
tected,
inside
mode
changes
into
THLD.
This
can
be
avoided
by
causing
short
circuit
in
DEF
(49pin)
to
“L”’=GND.
In
case
of
detection,
gain
can
be
automati-
cally
up
by
configulating
outside
DC!
(9pin)
band
pass
filter
which
picks
up
only
shock
element
out
of
tracking
error
signals
and
putting
it
in.
TO
amplifier
has
the
function
of
synthesizing
JP
pulse
and
cancelling
tracking
offset:
JP
pulse
is
set
by
JP
(14pin)
(THLD
is
detected
inside
).
|
.
Sled
servo
SLEQ
(28pin)
sets
response
characteristic.
Amplifier
after
SLEQ
(28pin)
has
muting
function,
and
mutes
SLOF
(38pin)
by
“H”
or
SLED
OFF
command.
Sled
feed
is
operated
by
means
of
current
input
to
SL-
(30pin)
and
SL+(31pin),
that
is,
by
connecting
to
output
port
of
micro
computer
by
resistance
and
setting
feed-
ing
gain
by
the
resistance
value.
.
Spindle
servo
This
configurates,
together
with
DSP,
servo
circuit
to
keep
disc
linear
velocity
at
a
scheduled
level.
This
re-
ceives
signal
from
DSP
by
CV-(39pin)
and
CV+(40pin),
and
sets
equalizer
characteristic
by
SP
(23pin),
SP-
(36pin)
and
SPD
(27pin)
which
output
to
SPD
(27pin).
SPG
(25pin)
is
set
by
resistance
with
which
amplifier
gain
of
12cm
mode
is
connected
to
standard
voitage.

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