Televes Coaxdata 1Gbps-HDTV COAX+PLC 1ETH+1SFP - Manual (Page 19)

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®
19
Step 0 ref.5930 Signal Measure:
First step is check output of signal
noise generator ref.5930 with
H45/H60 meter and save the measure
as a comparative reference for
measurements to be made later (Step
4).
After measuring signal level as
reference, it has to measure the noise
level in the coaxial network in folowing
steps.
Step 1 HeadEnd Noise Measure:
Disconnect the headend and check
the amount of noise generated in the
return path from 5-30 MHz, make sure
that there is more than 50 dBuV.
If readings exceed noise limits above,
it is necessary to use a diplexer filter
to avoid noise interference on
headend: ref.769220, for example.
Step 2 Coaxial Network Noise
Measure:
Then do the same
measure, but this time with the
distribution network. This is done by
connecting the input H45/H60 to
distribution network and checking that
the noise generated by all elements in
the 5-30 MHz return channel never
exceeds 25dB V.
μ
If the measurement exceeds the
reference value 25dBuV, must identify
that point of the distribution network
cause excess noise in the return
channel. Typically device connected
to any outlet.
Step 3 Coax Network Attenuation
with signal generator:
With level
reference obtained in Step 0, check
the attenuation of distribution network
in the return channel between the
input of the distribution network and
the worst case of all CoaxDATA
connection points. Must be equal or
less than 85 dB.
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