AK4524_12 Datasheet, PDF (16/32 Pages) Asahi Kasei Microsystems – 24Bit 96kHz Audio CODEC

[AK4524]
„ De-emphasis Filter
The DAC includes the digital de-emphasis filter (tc=50/15μs) by IIR filter. This filter corresponds to three frequencies
(32kHz, 44.1kHz, 48kHz). This setting is done via contorl register. This filter is always OFF at double speed and four
times speed modes.
No
DEM1
DEM0
Mode
0
0
1
0
0
44.1kHz
1
OFF
at reset
2
1
0
48kHz
3
1
1
32kHz
Table 7. De-emphasis control (DFS0=DFS1=“0”)
„ Soft Mute Operation
Soft mute operation is performed at digital domain. When SMUTE goes “H”, the output signal is attenuated by −∞ during
1024 LRCK cycles. When SMUTE is returned to “L”, the mute is cancelled and the output attenuation gradually changes
to 0dB during 1024 LRCK cycles. If the soft mute is cancelled within 1024 LRCK cycles after starting the operation, the
attenuation is discontinued and returned to 0dB. The soft mute is effective for changing the signal source without stopping
the signal transmission.
Soft mute function is independent to output volume and cascade connected between both functions.
SMUTE
0dB
A tte n u a tio n
1024/fs
(1)
1024/fs
(3)
-∞
GD
GD
(2)
Figure 6. Soft Mute
Notes:
(1) The output signal is attenuated by −∞ during 1024 LRCK cycles (1024/fs).
(2) Analog output corresponding to digital input has the group delay (GD).
(3) If the soft mute is cancelled within 1024 LRCK cycles, the attenuation is discontinued and returned to 0dB.
M0050-E-04
- 16 -
2012/01