OPTICOM OPERA - V 3.5 User Manual page 160

ERL (Echo Return
Loss)
C H A P T E R 6 : T E L E P H O N Y
T E S T I N G
Figure 6.36: Result Style Window
After this last step you may click on Finish and the selected diagram will appear
in the diagram pane as shown in Figure 6.37. An excerpt of the time signal
of one frame can be seen.
Figure 6.37: Time signals diagram
Figure 6.38 shows the diagram display when you choose the ERL diagram
type. The horizontal axis is a time axis for the amount of the delay, the vertical
axis shows the attenuation of the echo signal given in dB. Optionally you can
overlay the diagram with the acceptable tolerance curve according to ITU-T
Rec.G.131. Please note that the G.131 defines this curve for the one way delay,
whereas OPERA measures the real echo delay, which corresponds to the two
way delay of the ITU recommendation. Please be also aware, that G.131 is
defined for simple artificial test signals only and does not take into account
multiple echoes.
B A N D V O I C E Q U A L I T Y
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