Let’s look over the initial step of servo
1) when the tray is closed, first of all, it should be
checked whether there is disc or not on tray
2) CD laser is turn on and the lense is moved. if
there is a disc on tray, RF signal will appear
3) next, it should be confirmed which disc is that.
CD or DVD.
4) the following step will be done continuously CD -
Laser on -> move lense -> DVD - laser on ->
move lense. in according to disc type, there will
be RF signal…
5) after confirming disc, CD or DVD laser turn on
and focus servo is executed…
the below picture is related signals when DVD
disc is inserted
CD laser on
DVD laser on
PI
CD/DVD
CD_LD
DVD_LD
4)
9. Checking the second step of servo (2)
IC401 is called as Audio DAC, DAC means Digital-
Analog Convertor.
This IC receives digital signal from MPEG and con-
vert digital signal to analog signal, so we can hear
sound…
IC401 is connected with OP - AMP and an analog
Audio signal is amplified at the OP - A MP.
because the analog audio signal from DAC is a
very low level.
DAC_PCM_CLK : this is the system clock for
IC401
DAC_SCLK : this is standard clock to synchronize
the audio serial data
DAC_LRCK : R-chanel and L-chanel are selected
among the audio serial data by this
DAC_PCMOUT3 : serial audio data
DAC_PCM_CLK
DAC_SCLK
DAC_LRCK
ADAC_DATA
10. Checking the output of Audio signal
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