How Do I Use the Real-Time Vocoder?
Last updated: January 15, 2009
This topic is only applicable to the lab application.
The following procedure provides an example usage of Real-Time Vocoder. It is assumed that a mobile station's antenna output is connected to the test set's RF IN/OUT connector, an external audio source (such as a microphone) is connected to the test set's AUDIO IN port, and an external audio receiver (such as a loudspeaker) is connected to the test set's AUDIO OUT port.
General Procedure
-
Press the blue
SHIFT
key and then the green
Preset
key to fully reset the test set.
-
Follow the procedure described in
How Do I Set Up a Call and Make a Connection?
to establish a voice call.
-
Press the lower left
More
key until menu
3 of 5
of
Call Control
is displayed.
-
Press
AMR Setup
(
F5
).
-
Select
AMR Source
and then select
Real-Time Vocoder
from the pop-up menu.
-
Press the
Close Menu
(
F6
) key.
-
Press the
More
key on the lower left side of the display until menu
5 of 5
of
Call Control
is displayed.
-
Press
Real-Time Vocoder
(3).
-
Press
Real-Time Vocoder Parms
(
F1
). The Real-Time Vocoder Parameters menu is displayed. Set the parameters as desired and then press the
close menu
(
F6
) key when finished.
-
Speak into the mobile station. Verify that the voice is heard from the loudspeaker. The voice encoded by the mobile station is sent to the test set over the RF link. The test set then demodulates, decodes the signal and converts it to an analog signal output to the AUDIO OUT connector. The signal is then played by the loudspeaker.
-
Speak over the microphone (that is connected to AUDIO IN connector). The analog voice signal is input to the test set's AUDIO IN connector. The test set samples, encodes the signal, and modulates it onto the RF link. When the mobile station receives the RF signal, it demodulates, decodes, and converts the signal into an analog audio output to its speaker. Verify that the voice is heard from the mobile station's speaker.
-
A typical display during real-time vocoder operation is shown below. For an explanation of the encoder headroom and decoder headroom results, see
Real-Time Vocoder Headroom Information
.
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