Cisco Cisco 1 GHz GainMaker Amplifier Guía De Instalación
Chapter 3 Balancing and Setup
78
Methods of Generating and Monitoring Test Signals
The reverse RF test signals to be injected into the reverse path of the line extender
being balanced may be generated by the following.
being balanced may be generated by the following.
Multiple CW signal (tone) generator
Reverse sweep transmitter
The amplitude and tilt of the received test signals at the output of the reverse optical
receiver in the headend or hub may be measured and monitored using the
following.
receiver in the headend or hub may be measured and monitored using the
following.
Spectrum analyzer (when using a CW generator for test signals)
Signal level meter (when using a CW generator for test signals)
Reverse sweep receiver (when using a reverse sweep transmitter for test signal)
Communicating Test Results
The variance in relative amplitude and tilt of the received signal from desired
(reference) may be relayed to the field technician via the following.
(reference) may be relayed to the field technician via the following.
Radio, by a second technician in the headend or hub who is monitoring a
spectrum analyzer or signal level meter
spectrum analyzer or signal level meter
A dedicated forward TV channel whose associated modulator has its video input
being generated by a video camera focused on the spectrum analyzer display
being generated by a video camera focused on the spectrum analyzer display
An associated forward data carrier (if using a particular type of reverse sweep
system)
system)
If a portable reverse sweep generator with built-in forward data receiver is used to
generate the reverse test signals, only one technician is required to perform the
balancing. This type of system is becoming increasingly popular due to its ease of
use.
generate the reverse test signals, only one technician is required to perform the
balancing. This type of system is becoming increasingly popular due to its ease of
use.
In this case, the sweep system includes a combination reverse sweep receiver and
forward data transmitter, which is located in the headend or hub. The frequency
response characteristics of the received sweep signal, including relative amplitude
and tilt, are converted by the headend sweep receiver to a data format and
transmitted in the forward RF path as a data carrier by combining it into the forward
headend combiner.
forward data transmitter, which is located in the headend or hub. The frequency
response characteristics of the received sweep signal, including relative amplitude
and tilt, are converted by the headend sweep receiver to a data format and
transmitted in the forward RF path as a data carrier by combining it into the forward
headend combiner.
The portable sweep generator or data receiver that is injecting the test signals into
the reverse path in the field is simultaneously receiving the incoming data carrier via
the forward RF path, and converting it back to a sweep display which represents
what is being received by the headend unit.
the reverse path in the field is simultaneously receiving the incoming data carrier via
the forward RF path, and converting it back to a sweep display which represents
what is being received by the headend unit.