Polycom Vortex EF2241, Application Note

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6.
Lower the gain on the appropriate Output of the Vortex device to -10 dB.
It is important to set the gain structure correctly so that you don't clip the input audio
stage of the codec and that the Vortex device gets a good signal to perform processing
with. The nominal input and output of the codec is .3 V rms. The nominal input and
output of the Vortex device is .775 V rms. This equates to a difference of 8.24 dB between
the two nominal levels. For simplicity, you may round that value to 10 dB.
S
ETTING THE
AEC R
EFERENCE
U
SING A
V
IEW
S
TATION
EX
4.
Connect a monitor to Output 1 of the codec. By default, the composite output is enabled and the S-
Video output is disabled.
5.
Go to S
YSTEM
I
NFO
, A
DMIN
S
ETUP
, P
HONE
A
UDIO
, and check the E
CHO
C
ANCELLER
option. Ignore the
warning that is displayed on the screen about disabling the echo canceller and select OK.
6.
Once that is completed, make sure that the Input to the Vortex device is assigned to the
appropriate AEC Reference signal. Consult Reference Manual for the Vortex device or the Help file
in Conference Composer for more information.
T
ESTING THE
A
UDIO
I
NPUTS AND
O
UTPUTS
2.
Go to S
YSTEM
I
NFO
, A
DMIN
S
ETUP
, P
HONE
A
UDIO
, and check the E
CHO
C
ANCELLER
option.
You must enable the codec's internal echo canceller in order for the audio meter
described in Step 2 to work properly.
5.
Go to S
YSTEM
I
NFO
, D
IAGNOSTICS
, A
UDIO
, A
UDIO
M
ETER
and then speak into one of the microphones.
Your level should be around 0 on the meter. You may also use the loop-back feature to listen to
your own audio in the local room. That feature is under S
YSTEM
I
NFO
, D
IAGNOSTICS
, N
EAR
E
ND
L
OOP
.
6.
Go to S
YSTEM
I
NFO
, D
IAGNOSTICS
, A
UDIO
, G
ENERATE
T
ONE
to listen to a codec-generated 1 kHz tone.
7.
Go to S
YSTEM
I
NFO
, A
DMIN
S
ETUP
, P
HONE
A
UDIO
, and un-check the E
CHO
C
ANCELLER
option.
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