Measurement Examples; Example 1: Stand Alone Loop Measurement - OPTICOM OPERA - V 3.5 User Manual

C H A P T E R 6 :

6.8 Measurement Examples

For an inexperienced user of the OPERA™ measurement system, the following
examples might be useful to assist in your first measurements. The first example
demonstrates a typical loop measurement, while Example 2 will show a typical
application of measurements from a batch file.

6.8.1 Example 1: Stand Alone Loop Measurement

6.1.1.2 Signal Acquisition With OptiCall™
After connecting the OPERA™ system to the telephone network to be measured,
start the
Start|Programs|Opera|OptiCall (or click on the icon on the desktop). In the
OptiCall dialog, select the loop mode button. Make a right mouse button click
into the title bar of OptiCall and choose "Telephony Standard View" from the
drop down menu. Enter the phone number that is associated to line 0. Select
the file that contains a speech sample that will be sent through the network, in
the field Reference. In this example the WAVE file that is located in the
WaveFiles subfolder of the installation directory of your OPERA™ system is
used, "DefaultRefFile.wav".
Finally, enter the destination directory where the test files will be saved. Also
enter the root file name of your test files after the character #, e.g.
"D:\test#050700. Now press the start button. The connection will be
established, the speech sample will be sent and the test samples will be saved in
the location we have defined above.
Note:
The WAVE file "PSQMRef.wav" located in the OPERA™
installation directory should not be used with OptiCall™. This file
contains data that is 16 bit linear PCM coded. Since the POTS
interfaces would convert this to G.711, there would be an
additional, unwanted impairment of the test signal, caused by the
system.
When the test call has terminated two test files will be stored in the specified
destination directory. Assuming you that OptiCall was used in the Telephony
Standard mode, "050700-Line0.wav" is the relevant file when using
PESQ , "050700-Line1.wav" is the relevant file if an analysis of
performed with OPERA™. If OptCall was used in the Expert mode, take care to
choose the file recorded at the transmitting side for the Echo measurement and
the file recorded at the side which was listening only for the
measurement
At this time our measurement can be analyzed. Close OptiCall™ and bring
OPERA™ into the foreground again by clicking on it. If OPERA is not yet open,
choose Start|Programs|Opera|Opera. First use the PSQM algorithm. For this
purpose, select from the menu Masurement|Algorithm Parameters ... the
PSQM algorithm. To define the available properties click on the Properties...
button. Choose the settings shown in Figure 6.40, i.e. the IRS (telephone
T E L E P H O N Y B A N D
T E S T I N G
OptiCall™ program
157
V O I C E Q U A L I T Y
from the start
Echo
PSQM
menu
PSQM , or
shall be
or PESQ
Using the PSQM
Algorithm