saa7327 NXP Semiconductors, saa7327 Datasheet - Page 16

• Manufacturer Part Number: saa7327
• Description: Digital Servo Processor And Compact Disc Decoder With Integrated Dac For Video Cd Cd7 Ii
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.7.4
A digital level controller is present on the SAA7327 which
performs the functions of soft mute, full-scale, attenuation
and fade; these are selected via decoder register 0:
2000 Jun 26
Mute: signal reduced to 0 in a maximum of 128 steps;
(3/n) ms
Attenuate: signal scaled by 12 dB
Full-scale: ramp signal back to 0 dB level; from mute
takes (3/n) ms
Fade: activates a 128 stage counter which allows the
signal to be scaled up/down by 0.07 dB steps
– 128 = full-scale
– 120 = 0.5 dB (i.e. full-scale if oversampling filter
– 32 = 12 dB
– 0 = mute.
Digital servo processor and Compact Disc
decoder with integrated DAC for video CD (CD7 II)
used)
M
UTE
,
FULL
-
SCALE
,
ATTENUATION AND FADE
OK
Interpolation
Error
Fig.11 Concealment mechanism.
OK
Error
Hold
16
7.7.5
The peak detector measures the highest audio level
(absolute value) on positive peaks for left and right
channels. The 8 most significant bits are output in the
Q-channel data in place of the CRC bits. Bits 81 to 88
contain the left peak value (bit 88 = MSB) and
bits 89 to 96 contain the right peak value (bit 96 = MSB).
The values are reset after reading Q-channel data via
SDA.
Error
Error
P
Interpolation
EAK DETECTOR
OK
OK
MGA372
Product specification
SAA7327