Chapter 10
Measure Mode – Spectrum Tab
Ingress Resistance
266
DSAM Help User Guide
Rev. 001
–
Reset
– Manually resets the Peak Hold function.
–
Spectrum
– Displays the local Upstream Spectrum measure-
ment mode.
–
Pause (Shift, 8)
– Suspends measurement updates.
–
Marker A
– Sets Marker A as the active marker. (Use the left
and right arrow keys to move the marker.)
–
Marker B
– Sets Marker B as the active marker. (Use the left
and right arrow keys to move the marker.)
3
Press
ENTER
.
Ingress Resistance
The Ingress Resistance measurement mode displays a 20 MHz fixed
span. Within each frequency, the DSAM forms and continuously
updates a graph with 201 frequency points. The total ingress resis-
tance frequency range extends from 88 MHz to 108 MHz.
Initial measurements typically occur at the ground block with the home
disconnected from the network. Prior to an installation, use upstream
spectrum measurements to verify that the system does not exceed the
maximum acceptable level for ingress noise. After an installation,
check the noise level again to compare the previous reading and
confirm that install procedures or components did not create new
sources of ingress noise.
Measuring Ingress
Resistance
To run Ingress Resistance
1
Press
Measure
.
2
Press the
Spectrum
softkey.
NOTE
JDSU recommends using the Peak Hold option to verify the Return
Signal Generator Field View gain/loss.
21128026 R001 DSAM Help User Guide.book Page 266 Thursday, February 5, 2009 2:02 PM
