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09-10/2013 —
TELE-audiovision International —
全球发行量最大的数字电视杂志
tected and the signals them-
selves have excellent carrier-
to-noise ratio. Also the MER
measurements
confirmed
what could be deduced from
the spectral view – quality of
the output signal was very
good (see Graph 4).
The output power was
regulated to 90-95 dBμV
as can be seen in Graph 3.
The higher output was for
the higher frequency carrier
what makes sense as coax
cable attenuation increases
with frequency.
Then, we changed the
mode to 3x3 in which each
output (1 through 3) pro-
duced three different car-
riers. Figures 3 through 5
show the screenshots taken
from our signal analyzer and
Graphs 5 and 6 show the
power output and MER. Simi-
larly to the 1x8 mode, also
in this mode C/N was perfect
and the MER results were
down only slightly.
We did not notice any im-
pact on the MER due to tran-
sponder symbol rate. SUS
5581/33 NF LEGACY pro-
cessed the signal faultlessly
for both: very high and very
low symbol rates (30 Ms/
sec and 2.5 Ms/sec respec-
tively).
Now, the highlight came
for the SUS 5581 F. While
you can connect it directly to
a Quattro LNB, as mentioned
earlier you can also hook it up
to the trunk outputs of a SUS
5581/33 NF LEGACY. In such
a configuration you gain an-
other single cable output to
which you can connect up to
8 additional receivers. Figure
6 shows the spectral view of
SUS 5581 F output – 8 car-
riers each carrying a tran-
sponder selected by a re-
ceiver connected to the line.
The spectrum looked perfect
again. The output power was
exactly what SPAUN speci-
fied, that is 95 dμBV. MER
was down by about 1.2 dB
versus a direct LNB output.
This is a very good result if
we take into account that the
signal had to pass not one
but two multiswitches - see
Graph 7, 8.
After checking the satellite
signals performance we also
checked terrestrial signal
Graph 8.
Graph 7.
Graph 6.
Graph 5.
