Tripath Technology, Inc. – Preliminary Technical Information
Freeze Control
Addr
20h
Register Name
Freeze Control
Default
D7
0
D6
0
D5
0
D4
0
D3
0
D2
0
D1
0
D0
CHG
0
0
0
0
0
0
0
0
While CHG is set to ‘1’, any value that is written to a register takes effect immediately. However, while CHG
is cleared to ‘0’, any changes that are made to registers 00h through 6Fh and 80h through EFh will not take
effect until CHG is set to ‘1’. For example, if the user wanted to set all channels to a volume of F6h at the
same time, the user could clear CHG, set registers 25h through 2Ah to F6h one at a time, then set CHG to
‘1’.
Registers 70h through 7Fh and F0h through FFh are not affected by CHG.
Filter Bypass Control
Addr
21h
Register Name
Filter Bypass Control
Default
D7
DCB
0
D6
DEB
0
D5
DRB
0
D4
0
D3
0
D2
0
D1
0
D0
0
0
0
0
0
0
This register allows users to bypass any of the 3 digital filters incorporated in the TCD6001:
DCB = DC blocking filter
DEB = De-Emphasis filter
DRB = Droop correction filter
Setting these bits to ‘1’ bypasses the corresponding filter.
The DC blocking filter eliminates the DC component in an incoming signal. The frequency response of the
DC blocking filter is shown in Figure 1 for the 1X, 2X, and 4X modes.
Spectrum of De-emphasis Filter
Behaviour of DC Filter in Various Modes
2
0
10
0
32 kHz
44.1 kHz
48 kHz
-2
-10
-20
-30
-40
-50
-4
-6
-8
-10
1x mode
2x mode
4x mode
-12
10-2
10-1
100
101
102
102
103
104
105
Frequency in Hz
Frequency in Hz
Figure 1. DC Blocking Filter Characteristics
Figure 2. De-Emphasis Filter Characteristics
The De-Emphasis filter is used to re-shape the frequency response and reduce gain for frequencies above
3.183 kHz. It is only available in the 1X mode. If enabled, it needs to be selected for 1 of 4 possible input
data rates (32 kHz, 44.1kHz, or 48 kHz), as specified by bits D4 and D3 in the Sampling Rate and De-
Emphasis Control Register (address 22h).
The frequency response of the De-emphasis filter is shown in Figure 2 for all 3 input data rates.
The De-Emphasis Filter Selection bit is ignored for the 2X and 4X input data-sampling modes.
20
TCD6001 – JL/Rev. 0.9/07.05
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
