ak4648 AKM Semiconductor, Inc., ak4648 Datasheet - Page 56

• Manufacturer Part Number: ak4648
• Description: Stereo Codec With Mic/hp/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

■
The AK4648 includes the digital de-emphasis filter (tc = 50/15 μ s) by IIR filter. Setting the DEM1-0 bits enables the
de-emphasis filter (Table 36).
■
The AK4648 has 5 Band Equalizer on DAC block. The center frequencies and cut/boost amount are selected by
FBEQx3-0 bits (Table 37).
Note 56: These are the frequencies when the sampling frequency is 44.1kHz. These frequencies are proportional to the
Note 57: 100Hz is not center frequency but the frequency component lower than 100Hz is controlled.
Note 58: 10kHz is not center frequency but the frequency component higher than 10kHz is controlled.
FBEQ bit controls ON/OFF of this Equalizer.
MS0625-E-01
• Center frequency: 100Hz, 250Hz, 1kHz, 3.5kHz, and 10kHz (Note 56, Note 57)
• Cut/Boost amount: Minimum –10.5dB, Maximum +12dB, Step 1.5dB
De-emphasis Filter
5 Band Equalizer
FBEQA3-0: Select the boost level of 100Hz
FBEQB3-0: Select the boost level of 250Hz
FBEQC3-0: Select the boost level of 1kHz
FBEQD3-0: Select the boost level of 3.5kHz
FBEQE3-0: Select the boost level of 10kHz
sampling frequency.
DEM1
0
0
1
1
Table 37. Boost amount of 5 Band Equalizer
Table 36. De-emphasis Control
FBEQx3-0
DEM0
DH
EH
FH
0H
1H
2H
3H
8H
0
1
0
1
:
:
- 56 -
Boost amount
44.1kHz
48kHz
32kHz
Mode
OFF
+12.0dB
+10.5dB
− 10.5dB
+9.0dB
+7.5dB
− 7.5dB
− 9.0dB
0dB
:
:
(default)
(default)
[AK4648]
2007/06