Kenwood DP-3010 Service Manual page 41

DP-3010
76
CIRCUIT DESCRIPTION
in Normal Play, TC9201BF receives from TA8101N the TE
Signal from the ZCL1 pin and the SBAD Signal from ZCL2
the pin. — AD Conversion.
With the input of the CM-D Search Command NKIC(00) or
NKICF(Q0), Normal Play is put into operation. This is 0
Tracking Search.
At this time, the TE and SBAD Signals have already been
Through Rate controlled. By comparing the data that has
been Through Rate controlled and that that has been not,
Defect Detection and CD Player System Shock Detection
is executed.
The following explains about the defects, DFCT1 and
DFCT2.
(a) DFCT1 — Black Dot at Read Out Side Defect Detec-
tion
(b) DFCT2 — Interuption in information Layer Defect
Detection
The following explains about Defect and Shock Detection
operations.
) DFCT1 Detection:
In the TE Signal of TC9201BF, when the abscoiute vaiue of
the difference between the TE and TESR (Through Rate
Control} Signals surpasses N level (DEFECT-1 Command
Selection), the Defect Detection Signal, DFCT1. is emitted
internally. The DFCT pin is then switched from HiZ to VREF
'(See Diagram 7-30).
At this time, the SRCK data is set by the SRCK command.
It is possible to adjust the Through Rate Clock in 15 stages
(about 500 kHz x O ~ 15 CK). After the completion of
Defect Detection, the Pulse Delay can be adjusted in 15
stages with about 0.062ms as one unit of TN data.
I) DFCT2 Detection:
in the SB Signal, when the absolute value of the difference
between the SB and SBSR (Through Rate Control) Signals
surpasses M level (DEFECT-I] Command Seiection), the
Defect Detection Signal .DFCT2, is emitted in the same
way as DFCT1.
The DFCT pin is then switched from HiZ to VREF (See Dia-
gram 7-30).
At this time. SRCK is about 2.1 kHz. After the completion
of Defect Detection, the Pulse Delay can be adjusted in 15
stages with about 0.062ms as one unit of Tm data.
ill) SHOCK Detection
In the TE Signal, when the TESR Signal surpasses the —L
tevel in reference to VREF (10000 reference level at +2.2
V), a "SHOCK" occurs, at the same time the Shock Detec-
tion Pulse is emitted.
In Shock Detection, it is possible to control whether to use
the Detection Results or not by switching the GUP1 or
HYS1 from 1 or 0 as shown in the Timing Charts in Dia-
grams 7-31 and 32.
@ GUP1: When "1" during Shock Detection in Play,
the Tracking Servo is gained up.
@ HYS1: When "1" during Shock Detection in Play,
the Tracking Signal will have hysterisis char-
acteristics.
@ GUPCL: When "1" at the same time a defect is detect-
ed, the shock detected is void (DFCT =
DFCT1 + DFCT2)
~+ Shock Detection Reset, Defect Detection
Priority Operation
Make the final decision for the details of items | ~ Ill using
the result of system consideration.
The same goes for the usage of the TGUL, TGUH and
DFCT pins
ZCL1
zceL1
Through Rate
Control Signal
Z2C12
DFCT1
OFCT Output
DFCT2
DFCT Output
SHOCK
Shock Detection
DP-3010
CIRCUIT DESCRIPTION
DFCT2 Detection Shock Detection
rs VREF ni My Hl /~
ZCL2 Through Rate Control Signat
aye
of ===
f
' Tm (Timer Delay)
DFCT1 Detection
a __
res aes
Diagram 7-30 Defect/Shock Detection Shock Detection
Operation Period
Hexa- Cx {kHz) | Tw (msec) | Tw (msec) | T. (msec)
decimal |
T -
0.060 |
0.121 i
0.181
0.242
0.302
0.363
0423
0.484
0544
0.605
0.665
0.726
0.786
0847
0.907
0
1
2
3
4
5
6
7
8
9
A
B
c
D
E
F
Note: DEFECT-| and DEFECT-It data are set with the Shock
Command
Chart 7-7 TN, TM, TL, Relation between Data and
Setting Points
77