TCD6000 Datasheet, PDF (16/36 Pages) Tripath Technology Inc. – 6 CHANNEL CLASS-T DIGITAL AUDIO PROCESSOR USING DIGITAL POWER PROCESSINGTM TECHNOLOGY

Addr
20h
Register Name
Freeze Control
Default
Tripath Technology, Inc. – Preliminary Technical Information
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
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
D6
D5
D4
D3
D2
D1
D0
DCB DEB DRB 0
0
0
0
0
0
0
0
0
0
0
0
0
This register allows users to bypass any of the 3 digital filters incorporated in the TCD6000:
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.
B ehaviour of D C Filter in Various Modes
10
0
-10
-20
-30
-40
-50
-2
10
-1
10
0
10
Frequency in Hz
1x mode
2x mode
4x mode
1
2
10
10
Figure 1. DC Blocking Filter Characteristics
S pectrum of D e-emphasis Filter
2
32 kHz
44.1 kHz
0
48 kHz
-2
-4
-6
-8
-10
-12
2
3
4
5
10
10
10
10
Frequency in Hz
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.
A Droop correction filter is included in the TCD6000 to correct for droop and ripple in the frequency response
of the entire signal processing chain. The frequency response of the droop filter for the 1X, 2X, and 4X
sampling modes is shown below.
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TCD6000 – Rev. 1.0/09.04