AK4695 Datasheet, PDF (52/107 Pages) Asahi Kasei Microsystems – 24bit 4ch CODEC with MIC/HP/SPK/LINE-AMP

[AK4695]
Transfer function (2nd order)
1 + z ^1
1 + z ^1
H(z) = A
xA
1 + Bz ^1
1 + Bz ^1
The cut-off frequency should be set as below.
fc/fs  0.002 (fc min = 96Hz at 48kHz)
(1-2) Dynamic Volume Control Curve
The inflection points of the DVLC curve is set by three coordinate values (VL1X5-0, VL1Y5-0, VL2X5-0, VL2Y5-0,
VL3X4-0 and VL3Y4-0 bits). The setting of three inflection points are calculated the values of (X1_L, Y1_L), (X2_L, Y2_L),
(X3_L, Y3_L) in dB. The inflection points should be set in such a way that VL1X ≤ VL2X ≤ VL3X, VL1Y ≤ VL2Y ≤ VL3Y.
And the each slope is set by L1G6-0, L2G6-0, L3G6-0 and L4G6-0 bits. X4_L is fixed full-scale, Y4_L is calculated by the
L4G value. The initial value of the DVLC gain is set by the L1G.
Full scale
(X3_L, Y3_L)
(X2_L, Y2_L)
L3G
L4G
(X4_L, Y4_L)
(X1_L, Y1_L)
L2G
L1G
(0, 0)
DVLC Input Level
Full scale
Figure 35. DVLC Curve for Low Frequency Range
VL1X/Y5-0 bits Dynamic Volume Control Point
VL2X/Y5-0 bits
[dB]
Step
00H
0
(default)
01H
1.5
02H
:
3.0
:
1.5dB
2EH
69.0
2FH
70.5
30H
N/A
:
:
N/A
3FH
N/A
Table 48. DVLC Point Setting for X/Y1, X/Y2 (N/A: Not available)
MS1463-E-01
- 52 -
2014/12