ML7037-003 Datasheet, PDF (47/87 Pages) LAPIS Semiconductor Co., Ltd. – Dual Echo Canceler & Noise Canceler with Dual Codec for Hands-Free

FEDL7037-003-03
ML7037-003
(14) CR13
CR13
When to alter
Initial value
B7
B6
ASOPAD1 ASOPAD0
I/E
I/E
0
0
B5
ASIPAD1
I/E
0
B4
ASIPAD0
I/E
0
B3
B2
LSOPAD1 LSOPAD0
I/E
I/E
0
0
B1
LSIPAD1
I/E
0
B0
LSIPAD0
I/E
0
B7-6 : Acoustic Echo Canceller SoutA Gain Level Control Registers
B5-4 : Acoustic Echo Canceller SinA Loss Level Control Registers
The echo attenuation of the echo canceller would decrease when the Echo Return Loss (E.R.L. = RoutA – SinA) is
positive (SinA > RoutA). A combination of the ASIPAD1 and the ASIPAD0 determines a loss level with the
ASIPAD to tune the Echo Return Loss adequate for the acoustic echo canceller. A combination of the ASOPAD1
and the ASOPAD0 determines a gain level with the ASOPAD so that the loss by the ASIPAD could be recovered
and the level diagram could be kept flat, if needed.
The ASIPAD is a signal processing to narrower the dynamic range so that the loss level is recommended to be 0dB
when the Echo Return Loss is known to be negative (SinA < RoutA).
Refer to Table 8 and Table 9.
Table 8 Acoustic Echo Canceller SoutA Gain Level (ASOPAD)
B7
(ASOPAD1)
0
0
1
1
B6
(ASOPAD0)
0
1
0
1
Level
0dB
+6dB
+12dB
+18dB
Table 9 Acoustic Echo Canceller SinA Loss Level (ASIPAD)
B5
(ASIPAD1)
0
0
1
1
B4
(ASIPAD0)
0
1
0
1
Level
0dB
-6dB
-12dB
-18dB
(Note)
(Note)
When Acoustic Echo Canceller Automatic SinA Level Control is enabled (ASLC-bit [CR12-B2] = ‘1’),
Set all of the ASOPAD1, the ASOPAD0, the ASIPAD1, and the ASIPAD0 to logic ‘0’ (initial value).
The alternation of the setting with these bits must be made either in the initial mode or while the RST pin
is a logic ‘0’ or the RST-bit [CR0-B6] is a logic ‘1’.
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