Kenwood DP-3010 Service Manual page 17

DP-3010
CIRCUIT DESCRIPTION
¢ Status Comparator
The AD converted data of the FEI, TSO, SBAD and RFRP
signals for each mode
{in Diagram 5-1, Page 18) is needed internally for
TC9201BF. The Status Converter is used for this AD con-
version. With the Up/Down Counter and DA Converter in
TC9201BF and the Status Converter in TA8101N working
together a "Follow-up/Comparator" AD Converter is con-
structed. Thus the four signals are digitalized (5 bit data)
as shown in Diagram 5-14 (Refer to TC9201BF Technical
Information for further details),
Focus Error Signal ———
Tracking Error Signal. ~ ———
Sub-beam Summed Signal ———
RF Ripple Signal ——
Tri-state
Detection
Also shown in Diagram 5-14, the circuit is designed so
that the Dynamic Range of the Comparator input is 0 —
VREF (+2.2 V).
Since the Comparator (CZC) Output is an Open Collector
Output, a 10 kM Pull-up AMP should be used.
TC9201 BF Side
Zcut
zc1
ZCL2
zc2
Diagram 5-14 Status Comparator Construction
DP-3010
CIRCUIT DESCRIPTION
1) Sub-beam Summed (SBAD) Signal Emitting Circuit
The Sub-beam Summed (SBAD) Signal is a Summed
Signal of Converter 2a and 2b (I—V) where the Focus
ON/OFF Half Norma! Signa! and the Disc Scratches (drop
out) detection information is used.
The SBAD signal. as shown in Diagram 5-1 (page 18), is
selected from the System Mode when needed, passed
through the Status Comparator (CZC) and is supplied to
the CMOS Servo Processor, TC9201BF.
SBAO
B
(F-2)
V ADD AMP
DFCT2 DFCT1
OFCT1 .......--+ Black Dot at Read Out Side.
WDE CT2:
sede ud Interruption in information Layer. /
Diagram 5-16 SBAD Signal Operation Wave Forms
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