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detected by the photodetector (PD).
- For a pre-mastered disc, similar to a CD, the signals are
recorded as pits on the surface of the disc, and the signals
are detected by the amount of light reflected when the laser
beams strikes the pits.
- For a recordable disc, the signals are recorded by
magnetizing the magnetic film on the surface of the disc and
there is no variation in the amount of light that is reflected, so
the signals are detected using the shifting of the polarization
of the reflected light due to the Kerr effect (*1).
2. The detected signals are input to pins 38 and 39 of the RF IC (IC1),
where they are amplified and then output from pin 32.
- By observing the input signals (between pins 38 and 39) and
the output signals (pin 32) on an oscilloscope, it is possible to
check the eye pattern.
3. Error correction of the amplified signals is performed by the MD
LSI (IC3:MN66616RA1) using EFM demodulation and ACIRC (*2)
and the signals are stored in the DRAM (IC72:MNV4400-T8T). At
this time, the cycle of the signals is adjusted by the LSI's clock in
order to eliminate any jitter that might result from irregular
revolution of the disc.
4. The signals are sequentially taken from DRAM (IC72) and send
back to MD LSI (IC3), where they are ATRAC (*3)-decorded,
exchange it for analog signal by using AD-DA CONVERTER LSI
(IC4:AK4518VF-E2), and output from pins 19 (left channel) and 20
(right channel).
5. The digital signals output from the MD LSI are input to pin 15 of
the A/D-D/A CONVERTER (IC4:AK4518VF-E2), where they are
converted to analog signals and then output from pins 19 (left
chabbel) and 20 (right channel).
6. The analog-converted signals are output to LINE OUT.
- The exchange of signals between the DRAM and the MD LSI
is performed using four data lines (pins 1, 2, 24, and 25 of the
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