General Description
R&S
®
CMW-B400B/-B405A
15
User Manual 1176.8116.02 ─ 04
To test the speech quality of the speaker path, an external audio generator provides an
audio signal that is routed to an AF IN or SPDIF IN connector. The audio signal is
encoded and modulated in the R&S
CMW and routed via the RF connection to the
DUT. The DUT demodulates and decodes the signal and sends the audio signal to its
loudspeaker. The artificial ear listens to the loudspeaker of the DUT and provides the
resulting audio signal to the external audio analyzer.
To test the speech quality of the microphone path, an external audio generator pro-
vides an audio signal that is routed to the artificial mouth. The DUT listens to the artifi-
cial mouth, encodes and modulates the audio signal and transmits it via the RF con-
nection to the R&S
CMW. The R&S
CMW demodulates and decodes the signal and
routes it via an AF OUT or SPDIF OUT connector to the external audio analyzer.
If supported by the external audio analyzer, it is recommended to use a digital setup
(use the SPDIF connectors and the scenario "External Digital Speech Analysis"). A
digital setup provides a higher accuracy than an analog setup.
3.2 Performing Audio Measurements
The required settings vary depending on the used scenario, the used type of audio test
signal and the test setup components.
However, the general procedure outlined below is applicable to all audio measure-
ments.
1. Connect the components of your test setup (see
2. In the audio application main view, at the top, select a scenario matching your test
setup.
3. If your test setup involves an RF speech connection / a speech codec:
a) On the "Speech Analysis" tab, select the application that will set up the speech
call ("Controlled by" setting).
Softkeys related to the controlling application are added to the softkey bar.
b) Establish a speech connection via the controlling application. You can use the
softkeys to access settings of the controlling application and to control the call
setup, see
chapter 4.6, "Additional Softkeys and Hotkeys"
In most signaling applications, you must select "Speech" as data source.
For LTE speech calls, you must configure the IMS server of the DAU for audio
tests.
For details, refer to the documentation of the controlling application.
4. If your test setup involves external equipment, configure it (for example an R&S
UPV).
5. If your test setup involves internal audio generators and measurements, configure
them:
Performing Audio Measurements
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