Matrix Amplification XT2000 Specifikace stáhnout pdf (Strana 12)

Digital Services Activation Meter (DSAM)

www.jdsu.com/nse

Applications

Sweepless Sweep® Mode

The JDSU Sweepless Sweep mode provides an economical solution

for service technicians to check forward path alignment and identify

frequency response issues. This mode scans the entire forward

spectrum, displaying all levels across all frequencies (as dened by

meter conguration). Technicians can adjust the reception of the node

amplier with this scan and then normalize the display by saving a

reference. The resultant display is a at zero level trace. Moving the

probe to the output test point of the RF amplier displays any changes

due to the amplier as a deviation (delta) from the reference display.

The same reference is used as technicians move down the cascade,

thus providing a simple tool to align succeeding ampliers and

compensating for the eects of each cable segment. The Forward

Sweep option lets users isolate the eects of headend level changes

and provides a more accurate continually referenced sweep. Sweepless

Sweep is also useful for aligning portions of the spectrum where there

are no active carriers to reference.

Sweepless Sweep provides a quick method to check cable system integrity

using active channels to sweep the forward path. The method does not use

inserted sweep points and no forward path headend gear is required.

Forward Sweep Option

During a forward sweep, existing video carriers (digital or analog) are

continuously referenced at the headend or hub site source, eliminating

any possibility of unintended and irrelevant variation in the response

due to change in any individual signal level at the source.

The DSAM-6300 oers fast forward sweep capabilities, especially in

systems with numerous digital channels. In spectrum areas that are

densely populated with QAM signals, these signals are referenced in

the headend with the SDA-5500 and measured in the eld with the

DSAM-6300, which eliminates the need for injected sweep signals

and avoids any possible interference to subscribers. Continuously

referenced sweep provides a more stable and accurate measurement

by minimizing the eects of headend level drift.

In unoccupied spectrum areas, the SDA-5500 headend transceiver

inserts sweep points at designated frequencies. This is extremely useful

for construction and plant extensions up to 1 GHz.

Forward sweep uses a unique referencing method to reveal accurately prob-

lems in the system without interfering with any of the analog or digital carriers.

Reverse Sweep Option

The return path can be problematic and needs maintenance at least

as often as the forward path. One of the best practices for preserving

a clean return path is to follow an active reverse sweep maintenance

plan. The DSAM-6300 has a built-in reverse sweep transmitter,

removing the need for a separate instrument to generate test signals. A

reverse sweep can uncover mismatch problems, revealed as standing

waves, or diplex lter roll-os that can severely degrade reverse band

service quality.

Tight reverse sweep points in the sweep plan display the entire return path

with better resolution, and help to nd mismatches or other problems in the

upstream transmission path.

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