[AK4679]
■ Digital HPF1
A digital High Pass Filter (HPF) is integrated for DC offset cancellation of the ADC input. The cut-off frequencies of the
HPF1 are set by HPFC1-0 bits (Table 38). It is proportional to the sampling frequency (fs) and default is 3.4Hz (@fs =
44.1kHz). HPFAD bit controls the ON/OFF of the HPF1 (Recommend HPF enable).
fc
HPFC1 bit
HPFC0 bit
fs=44.1kHz
3.4Hz
13.6Hz
108.8Hz
217.6Hz
fs=22.05kHz
1.7Hz
6.8Hz
54.4Hz
108.8Hz
fs=8kHz
0.62Hz
2.47Hz
19.7Hz
39.5Hz
0
0
1
1
0
1
0
1
(default)
Table 38. HPF1 Cut-off Frequency
■ Side Tone Volume (SVOLA)
The AK4679 has the channel independent side tone volume (5 levels, 6dB step). The volume can be set by the
SVAL/R2-0 bits. The volume is included at mixing path from ALC to 5-band EQ. The output data of ALC is changed
from 0 to –24dB.
SVAL/R2-0 bits
Gain
0dB
0H
1H
2H
3H
4H
(default)
−6dB
−12dB
−18dB
−24dB
N/A
Others
Table 39. Side Tone Volume A Code Table (N/A: Not available)
MS1402-E-06
2013/02
- 79 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
