參數(shù)資料
型號: AK4646EZ
廠商: ASAHI KASEI POWER DEVICES CORP
元件分類: 消費家電
英文描述: Stereo CODEC with MIC/SPK-AMP
中文描述: SPECIALTY CONSUMER CIRCUIT, PQCC32
封裝: 4 X 4 MM, 0.40 MM PITCH, LEAD FREE, PLASTIC, QFN-32
文件頁數(shù): 39/78頁
文件大?。?/td> 808K
代理商: AK4646EZ
[AK4646EZ]
MS0630-E-00
2007/06
- 39 -
2.
ALC Recovery Operation
The ALC recovery operation waits for the WTM2-0 bits (Table 26) to be set after completing the ALC limiter operation.
If the input signal does not exceed “ALC recovery waiting counter reset level” (Table 23) during the wait time, the ALC
recovery operation is done. The VOL value is automatically incremented by RGAIN1-0 bits (Table 27) up to the set
reference level (Table 28) with zero crossing detection which timeout period is set by ZTM1-0 bits (Table 25). Then the
IVL and IVR are set to the same value for both channels. The ALC recovery operation is done at a period set by WTM2-0
bits. When zero cross is detected at both channels during the wait period set by WTM2-0 bits, the ALC recovery operation
waits until WTM2-0 period and the next recovery operation is done.
For example, when the current VOL value is 30H and RGAIN1-0 bits are set to “01”, VOL is changed to 32H by the auto
limiter operation and then the input signal level is gained by 0.75dB (=0.375dB x 2). When the VOL value exceeds the
reference level (REF7-0), the VOL values are not increased.
When
“ALC recovery waiting counter reset level (LMTH1-0)
Output Signal < ALC limiter detection level (LMTH1-0)”
during the ALC recovery operation, the waiting timer of ALC recovery operation is reset. When
“ALC recovery waiting counter reset level (LMTH1-0) > Output Signal”,
the waiting timer of ALC recovery operation starts.
The ALC operation corresponds to the impulse noise. When the impulse noise is input, the ALC recovery operation
becomes faster than a normal recovery operation. When large noise is input to microphone instantaneously, the quality of
small level in the large noise can be improved by this fast recovery operation. The speed of first recovery operation is set
by RFST1-0 bits(Table 30).
ALC Recovery Operation Waiting Period
WTM2
WTM1
WTM0
0
0
0
128/fs
0
0
1
256/fs
0
1
0
512/fs
0
1
1
1024/fs
128ms
1
0
0
2048/fs
256ms
1
0
1
4096/fs
512ms
1
1
0
8192/fs
1024ms
1
1
1
16384/fs
2048ms
Table 26. ALC Recovery Operation Waiting Period
RGAIN1
RGAIN0
0
0
1 step
0
1
2 step
1
0
3 step
1
1
4 step
Table 27. ALC Recovery GAIN Step
(default)
8kHz
16ms
32ms
64ms
16kHz
8ms
16ms
32ms
64ms
128ms
256ms
512ms
1024ms
44.1kHz
2.9ms
5.8ms
11.6ms
23.2ms
46.4ms
92.9ms
185.8ms
371.5ms
GAIN STEP
(default)
0.375dB
0.750dB
1.125dB
1.500dB
相關(guān)PDF資料
PDF描述
AK4646 Stereo CODEC with MIC/SPK-AMP
AK4646EN Stereo CODEC with MIC/SPK-AMP
AK4647 Stereo CODEC with MIC/HP-AMP
AK4647VN Stereo CODEC with MIC/HP-AMP
AK4648 Stereo CODEC with MIC/HP/SPK-AMP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AK4647 制造商:AKM 制造商全稱:AKM 功能描述:Stereo CODEC with MIC/HP-AMP
AK4647VN 制造商:AKM 制造商全稱:AKM 功能描述:Stereo CODEC with MIC/HP-AMP
AK4647VQ 制造商:AKM 制造商全稱:AKM 功能描述:Stereo CODEC with MIC/HP-AMP
AK4648 制造商:AKM 制造商全稱:AKM 功能描述:stereo CODEC with MIC/HP/SPK amplifier
AK4648EC 制造商:AKM 制造商全稱:AKM 功能描述:Stereo CODEC with MIC/HP/SPK-AMP