How Do I Use Real-Time Vocoder?
Last updated: September 1, 2009
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?
to establish a voice call.
-
Press
TCH Parameters
(
F8
).
-
Press the
More
key until
2 of 3
of the
TCH Parms
is displayed.
-
Press
Speech Setup
(
F10
).
-
Press
Speech Source
and Select
Real-Time Vocoder
from the pop-up menu.
-
press the
Return
(
F12
) key.
-
Press the
More
key on the lower left side of the display until
3 of 3
of
call control
is displayed.
-
Select
Real-Time Vocoder
(
F2
).
-
Select
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 finish the setting.
-
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. Verify that the voice is heard from the mobile station's speaker. The analog voice signal inputs to the test set over the Audio In connector. The test set samples, encodes the signal, and modulates it onto the RF link. The mobile station when receiving the RF signal, then demodulates, decodes, and converts the signal into an analog audio output to its 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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