Chapter 10
Measure Mode – Spectrum Tab
Downstream Spectrum
256
DSAM Help User Guide
Rev. 001
Marker Information
Area
The Downstream Spectrum measurement mode also contains an area
referred to as the Marker Information Area (area below the graph).
This area consists of the marker name, carrier frequency (in MHz), and
measured signal level for the frequencies which the markers are on.
The black square around the letter A or B below the graph displays the
active marker. The Peak Hold levels and the delta value (in dB)
between the peak hold levels are also displayed. If Peak Hold is
disabled, the live levels and the delta value (in dB) between the live
levels are displayed.
Setting the Center
Frequency
To set the center frequency
1
Press the
Settings
softkey.
2
Using the arrow keys, select
Center Frequency
.
3
Press
ENTER
.
4
Using the arrow keys and the alphanumeric keypad, enter the
center frequency in MHz
.
5
Press the OK softkey.
Using the Low
Pass Filter
The Low Pass Filter produces more accurate readings in the upstream
path when it is turned on. When the Low Pass Filter is on, it filters out
all of the downstream channels. JDSU does not recommend using the
Low Pass Filter for the downstream frequencies.
To use the Low Pass Filter
1
Press the
Settings
softkey.
2
Using the arrow keys, select
Low Pass Filter
.
3
Press
ENTER
.
The Low Pass Filter toggles on.
Figure 234
Downstream Spectrum – Center Frequency
21128026 R001 DSAM Help User Guide.book Page 256 Thursday, February 5, 2009 2:02 PM
