The DSAM Sweep measurement displays the
difference (delta) in level from the headend to the field DSAM or vice
versa. The main goal is to measure the frequency response of the cable
system distribution network. This is done by injecting active sweep points
(momentary narrow test carriers) over a range of frequencies at the input
of the system. The level of each sweep point is measured at both the input
and the output of the system. At the receiving end (output) the two values
are compared and the difference is displayed on DSAM, thereby emphasizing
any deviation caused by the network. As an alternative to active test
sweep points injected around a channel, the actual broadcast video carrier
can be used as a reference carrier for that frequency. An optimized sweep
plan will include both active sweep points, representing unused frequency
bands within the network's spectrum, as well as reference carriers.
This exclusive Stealth Sweep™ technology is patented by JDSU and
minimizes any possibility of service interference.
Both directions of the network can be swept. Forward sweep is accomplished
with a transceiver and measurement system in the headend or hub site,
such as the SDA-5500 Stealth Sweep Transceiver. It transmits and measures
active sweep points as well as measures reference carriers. Multiple field
DSAMs can be used at the same time with a common SDA-5500. Typically the
headend technician or network engineer is responsible for an accurate
forward sweep plan within the SDA-5500 transceiver.
Reverse sweep is accomplished in a similar way except that only active
sweep points are transmitted and measured by the DSAM field meter and
the SDA-5500 receives and measures the sweep points at the headend or
hub site. Only a single field user at a time can perform reverse sweep
with the SDA-5500. Larger networks typically will use a SDA-5510 Stealth
Reverse Sweep Manager to handle only reverse sweep for multiple field
users and configure the SDA-5500 for only forward sweep requirements.
The Sweepless sweep (optional purchase required) allows you to get the
sweep information without a transmitter.
MAIN FEATURES:
- Display of both forward and reverse sweep modes (Optional Purchase Required)
- One pair of vertical measurement markers.
- Sweep limit value along with a pair of associated horizontal markers
and a PASS/FAIL indicator.
- Ability to save multiple static measurement files as well as reference
files.
- Ability to view saved files as static files and reference files.
- Ability to Auto Reference, Zoom and Pause measurements.
The DSAM Sweep measurement in conjunction with the appropriate headend
SDA equipment provides Forward Sweep and Reverse Sweep measurement modes
that measure and display CATV system response.