[AK4675]
■ Digital Volume Control for Recording of Received Voice (DATT-B)
The AK4675 has a digital output volume control (DATT-B: 256 levels, 0.5dB step, Mute) for recording of received voice.
The volume can be set by the BVL7-0 bits. The volume is included in front of an SRC-B block. The input data of SRC-B
is changed from +12 to –115dB or MUTE. This volume has a soft transition function. The transition time between set
values of BVL7-0 bits is 256/fs2. It takes 256/fs2 (=32ms@fs2=8kHz) from 00H (+12dB) to FFH (MUTE).
BVL7-0
00H
01H
02H
:
Gain
+12.0dB
+11.5dB
+11.0dB
:
Step
0.5dB
18H
:
0dB
:
(default)
FDH
FEH
FFH
−114.5dB
−115.0dB
MUTE (−∞)
Table 38. Digital Volume B Code Table
■ Digital Volume Control for Received Voice (DATT-C)
The AK4675 has a digital output volume control (DATT-C: 256 levels, 0.5dB step, Mute) for received voice. The volume
can be set by the CVL7-0 bits. The volume is included in front of SDTOB output. The input data of SRC-C is changed
from +12 to –115dB or MUTE. This volume has a soft transition function. The transition time between set values of
CVL7-0 bits is 256/fs2. It takes 256/fs2 (=32ms@fs2=8kHz) from 00H (+12dB) to FFH (MUTE).
CVL7-0
00H
01H
02H
:
Gain
+12.0dB
+11.5dB
+11.0dB
:
Step
0.5dB
18H
:
0dB
:
(default)
FDH
FEH
FFH
−114.5dB
−115.0dB
MUTE (−∞)
Table 39. Digital Volume C Code Table
■ Side Tone Volume Control for B/T Phone Call (SVOLB)
The AK4675 has a side tone volume control (5 levels, 6dB step) for B/T phone call. The volume can be set by the SVL2-0
bits. The volume is included at mixing path from SRC-A to DATT-C. The output data of SRC-A is changed from 0 to
–24dB.
SVB2-0
0H
Gain
0dB
(default)
1H
2H
3H
4H
−6dB
−12dB
−18dB
−24dB
N/A
Others
Table 40. Side Tone Volume B Code Table (N/A: Not available)
MS0963-E-00
2008/05
- 85 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
