ASAHI KASEI
[AK4140]
Audio Sampling Rate
The AK4140 supports 3 sampling rates as 32kHz, 44.1kHz and 48kHz.
FS1
0
FS0
0
Sampling rate
32kHz
0
1
1
0
44.1kHz
48kHz
(default)
1
1
(Reserved)
Table 4. Sampling rate select
Digital High Pass Filter
The AK4140 has a digital high pass filter for DC offset cancellation. The cut-off frequency of the HPF is 1Hz
(@fs=48kHz) and scales with sampling rate (fs).
Pilot/SAP/Noise Detection (read)
PILOT bit: Pilot Signal Detection
Pilot signal
Detected
PILOT bit
1
0
Not detected
(default)
Table 5. Pilot Signal Detection
0 Æ 1 :
Pilot Signal Level ≥ Pilot Threshold Level (PTHR1,0 bit)
+ Pilot Hysteresis Level (PHYS1,0 bit) / 2 (in dB)
1 Æ 0 :
Pilot Signal Level < Pilot Threshold Level (PTHR1,0 bit)
- Pilot Hysteresis Level (PHYS1,0 bit) / 2 (in dB)
SAP bit: SAP Signal Detection
SAP signal
Detected
Not detected
SAP bit
1
0
(default)
Table 6. SAP Signal Detection
0 Æ 1 :
SAP Signal Level ≥ SAP Threshold Level (STHR1,0 bit)
+ SAP Hysteresis Level (SHYS1,0 bit) / 2 (in dB)
1 Æ 0 :
SAP Signal Level <SAP Threshold Level (STHR1,0 bit)
- SAP Hysteresis Level (SHYS1,0 bit) / 2 (in dB)
MS0547-E-01
2007/03
- 18 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
