TELE-audiovision - The World’s Largest Digital TV Trade Magazine - page 76

TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine
— 1 -12/2013
clean – there were hardly
any spurious (unwanted)
signals between the SCR
carriers. C/R ratio was in
excess of 35 dB! You do not
have such comfortable con-
ditions when dealing with a
regular satellite signal.
We checked the strength
of output signals (Channel
Power) of all the products.
In every case, the channel
power of single cable out-
puts was regulated to the
value specified by SPAUN.
The conclusion: no matter
for which carrier your re-
ceiver is configured it will be
supplied with equally strong
signal. Depending on the
model, the trunk outputs ei-
ther simply repeat the input
with a small loss, amplify it
or amplify it and regulate it
to a fixed value. See how it
looks on our graphs (Graph
1, 2, 3).
Please note that we pro-
vide you with only a selec-
tion of graphs we created
for every model. Otherwise,
this report would be very
lengthy and not suitable for
a magazine. But you can
believe us — the models
not documented in this test
report had very similar per-
And what about quality of
the output signal? Is it de-
graded significantly or only
marginally? The next graphs
(Graph 4, 5, 6) reveal the
truth: they are showing
the modulation error ratio
(MER) of the output signal
and the input signal in one
graph. MER is only slightly
worse at the output.
Additionally, we observed
a regularity – for the carri-
ers of higher frequency MER
is slightly worse than that
for the carriers of lower fre-
quency. However, the differ-
ence is so small that it is not
recognizable by the receiv-
ers of the end users.
We also tested the per-
formance for terrestrial sig-
nal (of course for the mod-
els supporting this signal)
and can confirm that signal
loss is below the specified
value (4 dB).
Finally, we connected a
real receiver to various mul-
tiswitches and found out
that channel zapping is re-
ally fast for single cable sig-
nal. It is important because
in such configuration this is
Graph 1.
Graph 2.
Graph 3.
1...,66,67,68,69,70,71,72,73,74,75 77,78,79,80,81,82,83,84,85,86,...260
Powered by FlippingBook