
ASAHI KASEI 
[AK4683] 
MS0427-E-01 
2005/11 
- 47 - 
De-emphasis Filter Control 
The AK4683 includes the digital de-emphasis filter (tc=50/15μs) by IIR filter corresponding to four sampling 
frequencies (32kHz, 44.1kHz, 48kHz and 96kHz). When DEAU bit=“1”, the de-emphasis filter is enabled automatically 
by sampling frequency and pre-emphasis information in the channel status. The AK4683 goes this mode at default. 
Therefore, in Parallel Mode, the AK4683 is always placed in this mode and the status bits in channel 1 control the 
de-emphasis filter. In Serial Mode, DEM0/1 and DFS bits can control the de-emphasis filter when DEAU bit is “0”. The 
internal de-emphasis filter is bypassed and the recovered data is output without any change if either pre-emphasis or 
de-emphasis Mode is OFF. 
PEM 
FS3 
FS2 
FS1 
1 
0 
0 
0 
1 
0 
0 
1 
1 
0 
0 
1 
1 
1 
0 
1 
1 
(Others) 
0 
x 
x 
x 
Table 51. De-emphasis Auto Control at DEAU bit = “1”  (default) 
PEM 
DFS 
DEM1 
1 
0 
0 
1 
0 
0 
1 
0 
1 
1 
0 
1 
1 
1 
0 
1 
1 
0 
1 
1 
1 
1 
1 
1 
0 
x 
x 
Table 52. De-emphasis Manual Control at DEAU bit = “0” 
System Reset and Power-Down 
The AK4683 has a power-down mode for all circuits by PDN pin can be partially powerd-down by PWN bit. The 
RSTN2 bit initializes the register and resets the internal timing. The AK4683 should be reset once by bringing PDN pin 
= “L” upon power-up.
PDN pin: All analog and digital circuit are placed in the power-down and reset mode by bringing PDN pin = “L”. All 
the registers are initialized, and clocks are stopped. Reading/Witting to the register are disabled. 
RSTN2 bit (Address 00H; D0):  
All the registers except PWN and RSTN2 bits are initialized by bringing RSTN2 bit = “0”. The internal 
timings are also initialized. When RSTN2 bit = “0”, the clock are output but SDTO pin is hold to “L”. 
Witting to the register is not available except PWN and RSTN2 bits. Reading to the register is disabled. 
PWN bit (Address 00H; D1):  
The clock recovery part is initialized by bringing PWN bit = “0”. In this case, clocks from PLL are stopped. 
The registers are not initialized and the mode settings are kept. Writing and Reading to the registers are 
enabled. 
FS0 
0 
0 
1 
0 
Mode 
44.1kHz 
48kHz 
32kHz 
96kHz 
OFF 
OFF 
x 
DEM0 
0 
1 
0 
1 
0 
1 
0 
1 
x 
Mode 
44.1kHz 
OFF 
48kHz 
32kHz 
OFF 
OFF 
96kHz 
OFF 
OFF 
(default)