
ASAHI KASEI
[AK4683]
MS0427-E-01
2005/11
- 46 -
Sampling Frequency and Pre-emphasis Detection
The AK4683 has two methods for detecting the sampling frequency as follows.
1. Clock comparison between recovered clock and XTI/MCLK2
2. Sampling frequency information on channel status
Those could be selected by XTL1, 0 bits. And the detected frequency is reported on FS3-0 bits.
XTL1
XTL0
0
0
0
1
1
0
1
1
XTI/MCLK2 Frequency
11.2896MHz
12.288MHz
24.576MHz
(Use channel status)
default
Table 47. Reference XTI/MCLK2 frequency
Except XTL1,0= “1,1”
XTL1,0= “1,1”
Register output
fs
Consumer
mode
(Note 2)
Byte3
Bit3,2,1,0
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
( 1 0 0 0 )
( 1 0 1 0 )
( 1 1 0 0 )
( 1 1 1 0 )
Professional mode
FS3
FS2
FS1
FS0
Clock comparison
(Note 1)
Byte0
Bit7,6
0 1
Byte4
Bit6,5,4,3
0 0 0 0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
0
44.1kHz
Reserved
48kHz
32kHz
88.2kHz
96kHz
176.4kHz
192kHz
44.1kHz
Reserved
48kHz
32kHz
88.2kHz
96kHz
176.4kHz
192kHz
(Others)
1 0
1 1
0 0
0 0
0 0
0 0
0 0 0 0
0 0 0 0
1 0 1 0
0 0 1 0
1 0 1 1
0 0 1 1
Note1: At least
±
3% range is identified as the value in the Table 48. In case of intermediate frequency of those two,
FS3-0 bits indicate nearer value. When the frequency is much bigger than 192kHz or much smaller than
32kHz, FS3-0 bits may indicate “0001”.
Note2: When consumer mode, Byte3 Bit3-0 are copied to FS3-0 bits.
Table 48. fs Information
The pre-emphasis information is detected and reported on PEM bit. This information is extracted from channel 1 at
default. It can be switched to channel 2 by CS12 bit in control register.
PEM
Pre-emphasis
Byte 0
Bits 3-5
≠
0X100
0X100
0
1
OFF
ON
Table 49. PEM in Consumer Mode
PEM
Pre-emphasis
Byte 0
Bits 2-4
≠
110
110
0
1
OFF
ON
Table 50. PEM in Professional Mode