Chapter 11
Measure Mode – Sweep Tab
Forward Sweep
DSAM Help User Guide
Rev. 001
273
Sweepless Sweep
Sweepless Sweep (additional purchase required) enables you to
retrieve sweep information without a transmitter. Carrier levels derived
from the channel plan are measured and recorded to compare with the
levels of the same carriers at a different point in the network.
Reverse
Alignment
Reverse Alignment (available only on DSAM-6000) enables signals to
be transmitted in the upstream spectrum and the levels to be read
when received at the SDA sweep transceiver in the headend. It is
especially useful for measuring the tilt in the spectrum.
Forward Sweep
Forward Sweep (additional purchase required and only applicable for
DSAM-6000) uses a headend transceiver to measure carrier levels
and, when necessary, to inject short sweep pulses. When stable
carriers are present, they can be referenced to create a sweep
response without injecting any sweep pulses. This minimizes any
subscriber interference as a result of sweep testing.
In Forward Sweep, the headend transceiver communicates with the
field DSAM by telemetry transmitted on a forward frequency. The
telemetry provides the sweep level results, as measured in the
headend, downstream to the DSAM which compares the results to the
local sweep results. The final display is the difference between the two
measurements resulting in a delta graph. A reference file is captured,
typically at the node amp output, before moving to the next amp. The
DSAM compares the delta between the reference file and the current
sweep measurement and displays the difference.
Figure 247
Measure Mode – Sweep Tab
21128026 R001 DSAM Help User Guide.book Page 273 Thursday, February 5, 2009 2:02 PM
