Chapter 8
Measure Mode – Basic Tab
Basic Measurement Modes
150
DSAM Help User Guide
Rev. 001
Basic Measurement Modes
The functions under the Basic tab of the DSAM Measure mode provide
the following measurement modes for viewing and analyzing CATV
channels:
Level
Views and analyzes the signal level of each carrier within a channel
(as defined by the active channel plan).
MiniScan
Views and analyzes the carrier levels of up to twelve channels and
displays the results on a single screen.
Full Scan
Views and analyzes the carrier levels of the entire channel plan at a
time and displays the video and audio levels of a carrier on a single
screen.
Tilt
Analyzes and displays the signal level and tilt calculation of up to
twelve channels and displays the results on a single screen.
Constellation
Displays a constellation grid of the demodulated digital Quadrature
Amplitude Modulation (QAM) type (64 QAM, 128 QAM or 256 QAM)
signal prior to error correction. This option is only available on specific
DSAM models.
FDR
Provides a means of characterizing impedance mismatches in the
home wiring and is used to detect potential faults that could disrupt
signal transmission. This mode requires an LST-1700.
Return QAM
Generator
DSAM is equipped with this mode so you can evaluate problems in the
network arising due to phase and amplitude distortions. Generally
these problems need attention to take advantage of the higher
capacity of the 16 QAM or 64 QAM.
QAM Ingress
The QAM Ingress mode is a line plot which graphs signal error versus
frequency of QAM signals. This mode supports Ingress Under Carrier
for QAM 64 and QAM 256 signals. (Additional purchase required.)
Hum
Displays the total hum percentage for a specified channel over a 1 kHz
span. (Additional purchase required.)
21128026 R001 DSAM Help User Guide.book Page 150 Thursday, February 5, 2009 2:02 PM
