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| AK4637EN Datasheet, PDF (51/96 Pages) Asahi Kasei Microsystems – 24bit Mono CODEC with MIC/SPK-AMP | |||
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[AK4637]
1. ALC Limiter Operation
During ALC limiter operation, when output level exceeds the ALC limiter detection level (Table 29), the
VOL value is attenuated automatically by the amount defined by the ALC limiter ATT step (Table 30).
(Once this ALC limiter operation is started, attenuation will be repeated sixteen times.)
After completing the attenuate operation, unless ALC bit is changed to â0â, the operation repeats when
the input signal level exceeds ALC limiter detection level.
LMTH2 LMTH1 LMTH0 ALC Limiter Detection
bit
bit
bit
Level
ALC Recovery Counter Reset Level
0
0
0 ALC Output ï³ ï2.5dBFS ï2.5dBFS > ALC Output ï³ ï4.1dBFS (default)
0
0
1 ALC Output ï³ ï2.5dBFS ï2.5dBFS > ALC Output ï³ ï3.3dBFS
0
1
0 ALC Output ï³ ï4.1dBFS ï4.1dBFS > ALC Output ï³ ï6.0dBFS
0
1
1 ALC Output ï³ ï4.1dBFS ï4.1dBFS > ALC Output ï³ ï5.0dBFS
1
0
0 ALC Output ï³ ï6.0dBFS ï6.0dBFS > ALC Output ï³ ï8.5dBFS
1
0
1 ALC Output ï³ ï6.0dBFS ï6.0dBFS > ALC Output ï³ ï7.2dBFS
1
1
0 ALC Output ï³ ï8.5dBFS ï8.5dBFS > ALC Output ï³ ï12.0dBFS
1
1
1 ALC Output ï³ ï8.5dBFS ï8.5dBFS > ALC Output ï³ ï10.1dBFS
Table 29. ALC Limiter Detection Level/ Recovery Counter Reset Level
Output
ATT Amount [dB]
+0.53dBFS ⤠Output Level (*)
0.38148
â1.16dBFS ⤠Output Level < +0.53dBFS
0.06812
LM-LEVEL ⤠Output Level < â1.16dBFS
0.02548
(*) Comparison with the next output data.
Table 30. ALC Limiter ATT Step
015010680-E-00
- 51 -
2015/09
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