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03-04/2015
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46 TELE-audiovision International — The World‘s Leading Digital TV Industry Publication — 03-04/2015 —
TEST REPORT Improving Optical Signals
The GlobalInvacom Fi-
breIRS family of products
are specially designed for
top quality satellite and ter-
restrial TV distribution sys-
tems. “Fibre” is the key word
here. The basic idea of this
distribution system is a con-
version of the electrical sig-
nals coming off the satellite
to fiber optic signals right at
the LNB output or better yet
even inside a dedicated opti-
cal LNB, a system GlobalIn-
vacom pioneered. The result
is that the signals distributed
off the LNB use fibre optic
cables rather than the usual
coax cables. Thanks to the
very low signal attenuation
of fibre optic cables, long
distances (even in the range
of kilometers) do not pose
any problem.
More important than end-
lessly long cable runs in most
cases is the possiblity of lots
of signal splitting. If you split
an optical signal into n ports
you will get 1/n signal power
at each output. To be very
precise, slightly less than 1/n
due to some additional cou-
pling loss. So, you can not
split an optic signal endlessly
but nevertheless it is possible
to split it up to 32 times in
GlobalInvacom’s system and
keep the original signal qual-
ity at each split as good as at
the LNB’s output. But that’s
not all! If, at every fibre line
end, you use a quad optical-
to-electrical converter, you
The Ideal Amplifier known FibreIRS ODU this
system hugely expands the
number of possible outlets
fed by one single fibre optic
LNB.
How does it work? Let’s
assume that our system
consists of GlobalInvacom’s
optical LNB (GI Fibre MDU)
connected to a 1:32 optical
splitter (GI Split32pro). This
gives us 32 optical outputs
to which we could connect
optical-to-electrical con-
verters producing signals
“understandable” by satel-
lite receivers. If we use the
GlobalInvacom’s converters
(GI FibreIRS GTU) this gives
us four independent electri-
cal outputs just like from a
regular Quad LNB.
GI FibreIRS O2E Converter
Amazing: better signal at the output
than what goes in
But now instead of con-
necting the FibreIRS GTU
converter we can connect
the new converter - the GI
FibreIRS O2E. This is also
an optical-to-electrical con-
verter but its output is not
the same as that of the GI
FibreIRS GTU. The GI Fi-
breIRS O2E generates a
stacked signal containing
all sub bands of the original
satellite Ku-Band of both po-
larizations. So, its bandwidth
is not just about 1 GHz but
about 4 GHz. Its output is in
fact the same as the output
of another GlobalInvacom
product: the wholeband uni-
versal LNB FibreIRS LNBm.
So, now at the end of one
of the 32 fibre optic lines we
have an electrical wholeband
will get 32x4=128 outputs of
perfect signal from a single
LNB. That is the real poten-
tial of fibre optic installations.
While 128 outputs fed
by one single LNB already
seems to be quite a lot, what
do you do if you need even
more top quality outputs? Of
course, you can always mul-
tiply such systems starting
by installing more satellite
dishes. But there is a more
practical and elegant way.
GlobalInvacom came up
with the new FibreIRS O2E.
Together with the already