AK4124 Datasheet, PDF (15/24 Pages) Asahi Kasei Microsystems – 192KHZ/ 24BIT HIGH PERFORMANCE ASYNCHRONOUS SRC

ASAHI KASEI
[AK4124]
„ Soft Mute Operation
1. Manual mode
Soft mute operation is performed in the digital domain of the SRC output. Soft mute can be controlled by SMUTE pin.
When SMUTE pin goes “H”, the SRC output data is attenuated by −∞ within 1024 OLRCK cycles. When the SMUTE pin
goes “L” the mute is cancelled and the output attenuation gradually changes to 0dB during 1024 OLRCK cycles. If the
soft mute is cancelled before mute state after starting of the operation, the attenuation is discontinued and returned to 0dB
by the same cycles. The soft mute is effective for changing the signal source.
SMUTE
0dB
(1)
Attenuation
1024/fso
(3)
-∞
GD
GD
(2)
SDTO
Figure 9. Soft Mute Function (Manual Mode)
(1) The output data is attenuated by −∞ during 1024 OLRCK cycles (1024/fso).
(2) Digital output delay from the digital input is called the group delay (GD).
(3) If the soft mute is cancelled before attenuating to −∞ after starting the operation, the attenuation is discontinued and
returned to 0dB by the same number of clock cycles.
2. Semi-Auto mode
The soft mute is cancelled automatically by the setting of PLL2-0 pins (refer to Table 2), after the AK4124 detects the
rising edge (PDN pin = “L” → “H”) and the mute is continued during 4410/fso=100ms@fso=44.1kHz. After PDN pin =
“L” → “H” and when SMUTE pin is “H”, the mute is not cancelled.
PDN pin
“L”
SM UTE pin
Don’t care
“L”
0dB
A tte n u a tio n
-∞
SDTO
4410/fso
(1)
(2)
GD
Figure 10. Soft Mute Function (Semi-Auto Mode)
(1) The output data is attenuated by −∞ during 1024 OLRCK cycles (1024/fso).
(2) Digital output delay from the digital input is called the group delay (GD).
MS0288-E-01
- 15 -
2004/08