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Philips Semiconductors
CMOS digital decoding IC with RAM for
Compact Disc
REGISTER
Versatile pins interface
Note
1. Standby modes = CL, DA and RAB; normal operation.
a) MISC, SCLK, WCLK, DATA, CL11 and DOBM; 3-state.
b) CRIN, CROUT, CL16 and CLA; normal operation.
c) V1, V2, V3, V4 and V5; normal operation.
d) MOTO1 and MOTO2 - in standby 2 'CD-PAUSE'; normal operation.
e) MOTO1 and MOTO2 - in standby 1 'CD-STOP'; held LOW in PWM mode; 3-state in PDM mode.
Error corrector
The error corrector carries out t = 2, e = 0 error corrections
on both C1 (32 symbol) and C2 (28 symbol) frames. Four
symbols are used from each frame as parity symbols. The
strategy t = 2, e = 0 means that the error corrector can
correct two erroneous symbols per frame and detect all
erroneous frames.
The error corrector also contains a flag controller. Flags
are assigned to symbols when the error corrector cannot
ascertain if the symbols are definitely good. C1 generates
output flags which are read (after de-interleaving) by C2,
to help in the generation of C2 output flags.
The C2 output flags are used by the interpolator for
concealment of non-correctable errors. They are also
output via the EBU signal (DOBM) and the MISC output
2
with I
S for CD-ROM applications.
The flags output pin CFLG provides information on the
state of all error correction and concealment flags.
1998 Feb 16
ADDRESS
DATA
1 1 0 1
0 0 0 0
X X 0 1
X X 1 0
X X 1 1
0 1 X X
1 0 X X
1 1 X X
FUNCTION
4-line motor (using V4, V5)
Q-to-W subcode at V4
V4 = 0
V4 = 1
de-emphasis signal at V5
V5 = 0
V5 = 1
Audio functions
D
-
E
EMPHASIS AND PHASE LINEARITY
When de-emphasis is detected in the Q-channel subcode,
the digital filter automatically includes a de-emphasis filter
section. When de-emphasis is not required, a phase
compensation filter section controls the phase linearity of
the digital oversampling filter to
0 to 16 kHz.
D
IGITAL OVERSAMPLING FILTER
The SAA7345 contains a 2 to 4 times oversampling filter.
The filter specification of the 4
given in Table 2 and shown in Fig.12.
These attenuations do not include the sample and hold at
the DAC output or the DAC post filter.
When using the oversampling filter, the output level is
scaled 0.5 dB down, to avoid overflow on full-scale
sinewave inputs (0 to 20 kHz).
14
Product specification
SAA7345
INITIAL
Reset
Reset
1 within the band
oversampling filter is
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