JDS Uniphase DSAM-1500, Руководство пользователя

Страница: 292 / 362

Chapter 10 Measure Mode – Spectrum Tab
Downstream Spectrum
252 DSAM Help User Guide Rev. 001
2 Using the arrow keys, select one of the following options:
– Auto Reference (Shift, 9) – Enables you to automatically view
measurement results in the best reference setting on the
graph.
– 5 dB/div or 10 dB/div – Enables you to adjust the vertical
resolution of the graph for the best viewing.
– Zoom – Turns Zoom on and off. When zoom is on, it displays a
10MHz span centered around the current position of the active
marker.
– Peak Hold – Turns Peak Hold on and off. When Peak Hold is
turned on, it displays the highest level trace at each frequency
for an extended view of the noise isolation.
– Reset – Manually resets the Peak Hold function.
– Field View – Displays results in Field View measurement
mode.
– Downstream Spectrum – Displays the Downstream Spectrum
screen.
– Pause (Shift, 8) – Suspends measurement updates.
3 Press ENTER .
Downstream Spectrum
The Downstream Spectrum measurement mode (additional purchase
required, depending on the model type) enables you to view the entire
CATV downstream spectrum frequency range (4 MHz to 1 GHz) in 50
MHz span, and can zoom to a 10 MHz span. The frequency span is
determined by the center frequency you select. Within each frequency
span, the DSAM forms and continually updates a graph with 201
frequency points.
Downstream Spectrum provides a view over six (6) vertical subdivi-
sions that contain a dynamic range of 60 dB and the ability to view the
entire CATV downstream spectrum frequency range in 10 or 50 MHz
NOTE
For best reference setting results you may need to press the Auto
Reference button up to three times.
21128026 R001 DSAM Help User Guide.book Page 252 Thursday, February 5, 2009 2:02 PM