ak4640 ETC-unknow, ak4640 Datasheet - Page 32

• Manufacturer Part Number: ak4640
• Description: 16bit Codec With /hp/spk-ampl
• Manufacturer: ETC-unknow

ASAHI KASEI
The AK4640 includes the digital de-emphasis filter (tc = 50/15µs) by IIR filter. Setting the DEM1-0 bits enables the
de-emphasis filter (Table 16).
The BST1-0 bits control the amount of low frequency boost applied to the DAC output signal (Table 17) . If the BST1-0
bits are set to “10” (MID Level), use a 47µF capacitor for AC-coupling. If the boosted signal exceeds full scale, the analog
output clips to the full scale. Figure 21 shows the boost frequency response at –20dB signal input.
MS0273-E-00
De-emphasis Filter
Bass Boost Function
-10
-15
-20
-25
-5
0
0.01
DEM1
BST1
0
0
1
1
0
0
1
1
Figure 21. Boost Frequency (fs=44.1kHz)
Table 17. Low Frequency Boost Control
MIN
Boost Frequency (fs=44.1kHz)
Table 16. De-emphasis Control
DEM0
0
1
0
1
BST0
0.1
0
1
0
1
Frequency [kHz]
- 32 -
MAX
44.1kHz
48kHz
32kHz
Mode
OFF
Mode
MAX
MID
MIN
MID
OFF
1
Default
Default
10
[AK4640]
2004/03