[AK4679]
3. Example of ALC Operation
Table 35 and Table 36 show the examples of the ALC setting for mic recording and playback, respectively.
fs=8kHz
Operation
fs=44.1kHz
Operation
Register Name Comment
Data
01
0
Data
01
0
LMTH1-0
ZELMN
Limiter detection Level
−4.1dBFS
Enable
−4.1dBFS
Enable
Limiter zero crossing detection
Zero crossing timeout period
* ZTM1-0 bits should be equal to or
shorter than WTM2-0 bits.
ZTM1-0
01
32ms
11
23.2ms
WTM2-0
REF7-0
IVL7-0,
IVR7-0
Recovery waiting period
Maximum gain at recovery operation
001
E1H
32ms
+30dB
100
E1H
46.4ms
+30dB
Gain of IVOL
E1H
+30dB
E1H
+30dB
LMAT1-0
RGAIN1-0
RFST1-0
ALC
Limiter ATT step
Recovery GAIN step
Fast Recovery Speed
ALC enable
00
00
00
1
1 step
1 step
4 times
Enable
00
00
00
1
1 step
1 step
4 times
Enable
Table 35. Example of the ALC setting (Recording Path)
fs=8kHz
fs=44.1kHz
Register Name Comment
Data
01
0
Operation
Data
01
0
Operation
LMTH1-0
ZELMN
ZTM1-0
Limiter detection Level
−4.1dBFS
Enable
32ms
−4.1dBFS
Enable
23.2ms
Limiter zero crossing detection
Zero crossing timeout period
Recovery waiting period
01
11
WTM2-0
*WTM2-0 bits should be the same or
longer data as ZTM1-0 bits
001
32ms
100
46.4ms
REF7-0
IVL7-0,
IVR7-0
Maximum gain at recovery operation
A1H
91H
+6dB
0dB
A1H
91H
+6dB
0dB
Gain of IVOL
LMAT1-0
RGAIN1-0
RFST1-0
ALC
Limiter ATT step
Recovery GAIN step
Fast Recovery Speed
ALC enable
00
00
00
1
1 step
1 step
4 times
Enable
00
00
00
1
1 step
1 step
4 times
Enable
Table 36. Example of the ALC setting (Playback Path)
MS1402-E-06
2013/02
- 76 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
