5
5
6
7
8
5
6
7
8
CX-3016
F
E
D
C
B
A
After a focus close command is issued, the following procedures are performed irrespective of DVDs and CDs:
1. Measuring and optimizing the signal levels
The pickup lens initially moves away from the disc, and then toward the disc. When the pickup lens passes the focal
point, the FE, AS and RFENV signal levels are measured to optimize the FE and AS signal levels (1 and 2 shown in
the above diagram).
Near the disk
Away from the disk
Lens
VHALF
Focal point
FE
RFENV
AS
3
6
7
4
5
1
2
1.2 Optical disc controller (SODC) section (MNZS26EDCUB: IC1301)
The IC1301, an optical disc controller (SODC) for DVD-ROM/DVD players, is one of a signal processing LSI conforming
to the DVD standards.
This IC works as a servo controller for the focus, tracking and traverse operations, a spindle motor controller, a seek
controller, a digital signal processor for DVD-ROM/RAM reproduction (8/6 demodulation and error correction), and a
digital signal processor for CD-ROMs (error correction). In the DSC (Disc Servo Controller) employing an arithmetic
processor as a core, analog circuits such as A/D and D/A converters and PLL, and digital circuits including a PWM
converter and a cycle timer are contained. In the CIRC, a digital signal processor for CD-DA and CD-ROMs (EFM
demodulation and error correction), a spindle motor digital servo processor, and a 1-bit D/A converter with a digital
filter (with a secondary low-pass filter, differential OP amplifier output) are prepared. This LSI has easily realized a
complete CD/DVD-ROM system.
1.2.1 Focus close
FODRV
