ZyXEL Communications MSC1000G Series, Руководство пользователя

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Chapter 11 Profile Screens
Management Switch Card User’s Guide
352
The following table describes the labels in this screen.
11.7.7 VDSL2 Channel Profile Setup
Click the ChanProfile link at the top-right corner of the VDSL2 Template Setup screen to open
the screen shown below. Use this screen to view, add, modify and delete channel profiles.
Table 165
Profile > VDSL2 > LineProfile > Virtual Noise
LABEL DESCRIPTION
Virtual Noise This displays the virtual noise setting result in a graph.
If there is too much noise on a line, the allowed line speed may be reduced or the line
may not initialized. Virtual noise is the noise allowed on the line before the first line speed
adjustment occurs. MSC then uses a lower data rate on tones which you added a noise
level for the line initialization. A lower data rate increases a line’s stability and avoid the
line being easily dropped when actual noise occurs.
Preview Click this to update the virtual noise setting result according to your setting configured at
the bottom of the screen.
Downstream,
Upstream Select whether you want to enable virtual noise ( Enable ) or not ( Disable ) for
downstream and upstream transmissions.
Note: For a poor quality subscriber line, you should enable this and configure virtual noise
on tones where noise may occur.
Note: The higher the virtual noise, the lower the line speed.
Break Point This index number identifies each incremental break point.
Tone Index A tone is a sub-channel of VDSL band. DMT divides VDSL bands into many 4.3125 kHz
tones.
Enter an increased number (than previous row) from 0 to 4096 in this field that is also the
horizontal of the DPBOEPSD graph.
Frequency (kHz) This read-only field displays a frequency that equals the tone index multiple 4.3125 dBm/
Hz. This field automatically calculates after a
Tone Index value is entered.
PSD Level (-
140+PSD/2 dBm/
Hz) Enter the noise level (0~200) for the specified tone(s) where you expect noise may occur.
The actual PSD level will be -140 plus half of the value you specify (dBm/Hz). This setting
is then reflected in the Y-axis of the virtual noise graph after you click
Preview .
Modify Click this to save the settings to the MSC and return to the previous screen.
Cancel Click Cancel to reset the fields to your previous configuration.
Clear Click Clear to clear the fields to the factory defaults.