ak4140 AKM Semiconductor, Inc., ak4140 Datasheet - Page 18

• Manufacturer Part Number: ak4140
• Description: Digital Btsc Decoder
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
The AK4140 supports 3 sampling rates as 32kHz, 44.1kHz and 48kHz.
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 bit: Pilot Signal Detection
SAP bit: SAP Signal Detection
MS0547-E-01
Audio Sampling Rate
Digital High Pass Filter
Pilot/SAP/Noise Detection (read)
0
1
0
1
1 :
0 :
1 :
0 :
Pilot Signal Level ≥ Pilot Threshold Level (PTHR1,0 bit)
SAP Signal Level ≥ SAP Threshold Level (STHR1,0 bit)
SAP Signal Level <SAP Threshold Level (STHR1,0 bit)
Pilot Signal Level < Pilot Threshold Level (PTHR1,0 bit)
- SAP Hysteresis Level (SHYS1,0 bit) / 2 (in dB)
+ SAP Hysteresis Level (SHYS1,0 bit) / 2 (in dB)
FS1
0
0
1
1
Not detected
+ Pilot Hysteresis Level (PHYS1,0 bit) / 2 (in dB)
Not detected
- Pilot Hysteresis Level (PHYS1,0 bit) / 2 (in dB)
Pilot signal
SAP signal
Detected
Detected
Table 5. Pilot Signal Detection
Table 6. SAP Signal Detection
Table 4. Sampling rate select
FS0
0
1
0
1
PILOT bit
- 18 -
SAP bit
Sampling rate
(Reserved)
1
0
1
0
44.1kHz
32kHz
48kHz
(default)
(default)
(default)
[AK4140]
2007/03