AK4671_10 Datasheet, PDF (70/166 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/RCV/HP-AMP

[AK4671]
3. Example of ALC Operation
Table 31 and Table 32 show the examples of the ALC setting for mic recording and playback, respectively.
Register Name
LMTH1-0
ZELMN
ZTM1-0
WTM2-0
REF7-0
IVL7-0,
IVR7-0
LMAT1-0
RGAIN1-0
RFST1-0
ALC
Comment
fs=8kHz
Data
Operation
Limiter detection Level
01
−4.1dBFS
Limiter zero crossing detection
0
Enable
Zero crossing timeout period
* ZTM1-0 bits should be equal to or 01
32ms
shorter than WTM2-0 bits.
Recovery waiting period
001
32ms
Maximum gain at recovery operation E1H
+30dB
Gain of IVOL
E1H
+30dB
Limiter ATT step
00
1 step
Recovery GAIN step
00
1 step
Fast Recovery Speed
00
4 times
ALC enable
1
Enable
Table 31. Example of the ALC setting (Recording Path)
fs=44.1kHz
Data
Operation
01
−4.1dBFS
0
Enable
11
23.2ms
100
46.4ms
E1H
+30dB
E1H
+30dB
00
1 step
00
1 step
00
4 times
1
Enable
Register Name
LMTH1-0
ZELMN
ZTM1-0
WTM2-0
REF5-0
IVL7-0,
IVR7-0
LMAT1-0
RGAIN1-0
RFST1-0
ALC
Comment
fs=8kHz
Data
Operation
Limiter detection Level
01
−4.1dBFS
Limiter zero crossing detection
0
Enable
Zero crossing timeout period
01
32ms
Recovery waiting period
*WTM2-0 bits should be the same or 001
32ms
longer data as ZTM1-0 bits
Maximum gain at recovery operation A1H
+6dB
Gain of IVOL
91H
0dB
Limiter ATT step
00
1 step
Recovery GAIN step
00
1 step
Fast Recovery Speed
00
4 times
ALC enable
1
Enable
Table 32. Example of the ALC setting (Playback Path)
fs=44.1kHz
Data
Operation
01
−4.1dBFS
0
Enable
11
23.2ms
100
46.4ms
A1H
+6dB
91H
0dB
00
1 step
00
1 step
00
4 times
1
Enable
MS0666-E-02
- 70 -
2010/06