
CS6420
12
DS205PP2
Register 0
*
Denotes reset value
Table 3. Register 0 Bit Definitions
Mic - Microphone Preamplifier Enable
The microphone preamplifier described in the
Acoustic Interface
section is enabled by default, but
may be disabled by setting Mic to 0. Refer to the
Acoustic Interface
section for more details on us-
ing/disabling the Microphone Preamplifier.
TSD - Transmit Suppression Disable
The Transmit Supplementary Echo Suppression
function is a non-linear echo control mechanism.
The Transmit Suppression will introduce TSAtt
(see Register 3) dB of attenuation into the transmit
path only when there is speech detected in the re-
ceive path and no near-end speech. When only
near-end speech is present, or if there is no speech
in either direction, the suppression attenuation is
removed. By default, the transmit suppression
function is enabled.
GB - Graded Beta
The room-size adjustment scheme called “graded
beta,” provided for the acoustic echo canceller in the
b15
Mic
1
b14
TSD
0
b13
b12
b11
b10
b9
b8
b7
RVol
00100
b6
b5
b4
b3
b2
0
0
b1
0
0
b0
0
0
GB
10
ACC
00
TGain
00
Bits
Name
Function
Word
0
1*
0*
1
00
01
10*
11
00*
01
10
11
00000
00001
---
00100*
---
01010
01011
---
11101
11110
11111
00*
01
10
11
Operation
disable preamp
enable preamp
enable Tx suppression
disable Tx suppression
0.00 dB/ms
0.75 dB/ms
0.38 dB/ms
0.19 dB/ms
Normal
Clear
Freeze
reserved
+30 dB
+27 dB
15
Mic
Microphone Preamplifier Enable
14
TSD
Tx Suppression Disable
13-12
GB
Graded Beta
11-10
ACC
AEC Coefficient Control
9-5
RVol
Rx Volume Control
+18 dB
+0 dB
-3 dB
-57 dB
-60 dB
mute
0 dB
6 dB
9.5 dB
12 dB
4-3
TGain
Tx Analog Gain