ASAHI KASEI
[AK4550]
n
De-emphasis filter
The DAC of AK4550 includes the digital de-emphasis filter (tc=50/15us) by IIR filter. This filter corresponds to three
frequencies (32kHz, 44.1kHz, 48kHz). The de-emphasis filter selected by DEM0 and DEM1 is enabled for input audio
data. The de-emphasis is also disabled at DEM0=”1” and DEM1=”0”.
DEM1
DEM0
Mode
0
0
44.1kHz
0
1
OFF
1
0
48kHz
1
1
32kHz
Table 2. De-emphasis filter control
n
Digital High Pass Filter
The AK4550 has a Digital High Pass Filter (HPF) for DC-offset cancel. The cut-off frequency of the HPF is 3.4Hz at
fs=44.1kHz and the frequency response at 20Hz is –0.12dB. It also scales with the sampling frequency (fs).
M0068-E-01
-9-
2000/4
AKM [ ASAHI KASEI MICROSYSTEMS ]
