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LTE Signaling
R&S
®
CMW-KM5xx/-KS5xx
93
User Manual 1173.9628.02 ─ 16
A generator of the R&S
UPV feeds an audio signal via the AF 1 IN port to the speech
encoder of the audio board. The test signal is transmitted via the VoLTE connection to
the UE. The UE demodulates and decodes the signal and feeds the resulting audio
signal to its speaker. An analyzer of the R&S
UPV measures the audio signal of the
speaker.
If the UE has microphone and speaker jacks or a headset jack, connect the UE via an
audio cable to the R&S
UPV. Alternatively, you can position a microphone at the UE
speaker and a speaker at the UE microphone and connect them to the R&S
UPV. Use
a high quality microphone and speaker designed for that purpose, for example an artifi-
cial head.
Performing a speech quality test
The following sequence describes the configuration steps required at the R&S
CMW.
The R&S
UPV configuration is out of the scope of this document.
1. Set up the VoLTE connection as described in the previous sections.
2. Set up the two audio connections between the R&S
UPV and the UE and the two
audio connections between the R&S
UPV and the R&S
CMW.
3. Configure the audio settings of the R&S
CMW:
a) At the top of the "Audio Measurement 1" view, select the scenario "External
Analog Speech Analysis".
b) Press the "Config" hotkey to open the audio configuration dialog box.
c) Configure the input level compatible to the R&S
UPV generator output.
d) Configure the output level compatible to the R&S
UPV analyzer input.
A calibration procedure of the R&S
UPV may require specific level settings.
4. Configure the R&S
UPV. Calibrate it, if required.
5. Start the R&S
UPV generators and analyzers.
For more information about speech quality tests with an R&S UPV, refer to the follow-
ing documents:
●
Application note "1MA204", "Voice over LTE (VoLTE) Speech Quality Measure-
ments"
●
Application note "1GA62", "Test Automation Tool for POLQA
®
and PESQ
®
Speech
Quality Tests"
These documents are available for download at
2.3.3.6
Possible Extensions
While you perform audio tests or speech quality tests, you can vary connection param-
eters and study the effect on the audio quality.
With option R&S CMW-KM050, you can use the data application unit to add network
impairments to the downlink VoLTE connection. Thus you can simulate challenges of
real IP networks and test the effect on the speech quality.
Application Sheets
深圳德标仪器
135-1095-0799