ASAHI KASEI
[AK4564]
Filter Select 1
Addr
Register Name
D7
MIX1
0
D6
MIX0
0
D5
HPF3
0
D4
D3
D2
D1
D0
FSF
0
04H Filter Select 1
Default
HPF2-1 HPF2-0 HPF1-1 HFP1-0
0
0
0
0
FSF: Select sampling rate to match a coefficient of digital filter
0: fs = 48kHz (Default)
1: fs = 32kHz
HPF1: Select cut-off frequency of HPF1 in EQ block. This is 1st order and IIR filter.
Cut-off Frequency
HPF1-1
HPF1-0
fs=32kHz
OFF
fs=48kHz
OFF
Default
0
0
1
1
0
1
0
1
6kHz
6kHz
7.5kHz
9kHz
7.5kHz
9kHz
Table 9. Select cut-off frequency of HPF1
HPF2: Select cut-off frequency of HPF2 to revise frequency response. This is 1st order and IIR filter.
Cut-off Frequency
HPF2-1
HPF2-0
fs=32kHz
OFF
fs=48kHz
OFF
Default
0
0
1
1
0
1
0
1
100Hz
200Hz
300Hz
100Hz
200Hz
300Hz
Table 10. Select cut-off frequency of HPF2
HPF3: Select cut-off frequency of HP3 for wind-noise cut. This is 2nd order and IIR filter. The cut-off frequency is
fixed to 400Hz and is changed by FSF bit.
0: OFF (Default)
1: ON
MIX1-0: Select Mixing value in EQ block. When HPF1 is OFF, this circuit is also OFF.
MIX1
MIX0
Main : Sub
1: 1
Default
0
0
1
1
0
1
0
1
1: 1.25
1: 0.5
1: 0.75
Table 11. Select Mixing value
MS0140-E-01
2002/07
- 37 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
