[AK4372]
■ Soft Mute
Soft mute operation is performed in the digital domain. When the SMUTE bit changes to “1”, the output signal is
attenuated by −∞ during the ATT_DATA×ATT transition time (Table 18) from the current ATT level. When the SMUTE
bit is returned to “0”, the mute is cancelled and the output attenuation gradually changes to the ATT level during
ATT_DATA×ATT transition time. If the soft mute is cancelled before attenuating to −∞ after starting the operation, the
attenuation is discontinued and is returned to the ATT level by the same cycle. The soft mute is effective for changing the
signal source without stopping the signal transmission.
SMUTE bit
ATS bit
(1)
ATS bit
(1)
ATT Level
Attenuation
(3)
-∞
GD
GD
(2)
Analog Output
Figure 21. Soft Mute Function
Notes:
(1) ATT_DATA×ATT transition time (Table 18). For example, this time is 3712LRCK cycles (3712/fs) at ATS bit =
“1” and ATT_DATA = “128”(-63.5dB).
(2) The analog output corresponding to the digital input has a group delay, GD.
(3) If the soft mute is cancelled before attenuating to −∞ after starting the operation, the attenuation is discontinued
and it is returned to the ATT level by the same cycle.
MS0684-E-02
2008/12
- 27 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
