ak4646 AKM Semiconductor, Inc., ak4646 Datasheet - Page 36

• Manufacturer Part Number: ak4646
• Description: Stereo Codec With Mic/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

Register setting (Note 34)
(4) Gain Compensation (EQ0)
Gain Compensation is used to compensate the frequency response and the gain that is changed by Stereo Separation
Emphasis Filter. Gain Compensation is composed of the Equalizer (EQ0) and the Gain (0dB/+12dB/+24dB). E0A15-0,
E0B13-0 and E0C15-0 bits set the coefficient of EQ0. GN1-0 bits set the gain (Table 22). EQ0 bit controls ON/OFF of
EQ0. When EQ is OFF and the gain is 0dB, the audio data passes this block by 0dB gain. The coefficient should be set
when EQ0 bit = “0” or PMADL=PMADR= PMDAC bits = “0”.
MS0557-E-02
fs: Sampling frequency
fc
fc
K: Filter gain [dB] (Maximum +12dB)
1
2
: Pole frequency
: Zero-point frequency
E0A[15:0] bits =A, E0B[13:0] bits =B, E0C[15:0] bits =C
(MSB=E0A15, E0B13, E0C15; LSB=E0A0, E0B0, E0C0)
Transfer function
H(z) =
A = 10
K/20
A + Cz
1 + Bz
x
1 + 1 / tan (πfc
1 + 1 / tan (πfc
−1
−1
Gain[dB]
GN1
Table 22. Gain select of gain block (x: Don’t care)
0
0
1
2
1
/fs)
/fs)
K
Figure 28. EQ0 Frequency Response
,
B =
GN0
0
1
x
1 − 1 / tan (πfc
1 + 1 / tan (πfc
fc
- 36 -
1
+12dB
+24dB
Gain
0dB
fc
1
1
/fs)
/fs)
2
,
C =10
(default)
Frequency
K/20
x
1 − 1 / tan (πfc
1 + 1 / tan (πfc
2
1
/fs)
/fs)
[AK4646]
2007/05