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DATA
TECHNICAL
Manufacturer
GlobalInvacom Ltd., Great Britain
Web
E-mail
Phone
+44-1621-743440
Fax
+44-1621-743676
Model
QUAD GTU and QUATRO GTU
Function
Light-to-RF converters with quad/quatro outputs
Satellite
Frequency range
950–2150 MHz
Gain variation across band
7 dB
Nominal output level
70 dBµV (QUAD) and 75 dBµV (QUATRO)
Terrestrial band rejection
30 dB
DTT, DAB and FM
Frequency range for DTT
470-862 MHz
Frequency range for DAB
174-240 MHz
Frequency range for FM
88-108 MHz
Nominal output power
68 dBµV
Gain variation across band
5 dB
Noise figure @ max. gain
6 dB
IF band rejection
20 dB
Optical
Optical wavelength
1100-1650 nm
Optical power
-15 dBm to 0 dBm
DC
Voltage
10-20 V
Current consumption max.
220 mA @ 10 V (QUAD) 210 mA @ 10 V (QAUTRO)
Physical
Dimensions (without plastic)
109 x 136 x 50 mm
Jacek Pawlowski
TELE-audiovision
Test Center
Poland
+
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TELE-audiovision.com/10/09/globalinvacom
More about this company
Output #
Power
C/N
MER
dBµV
dB
dB
1
70.9
32.8
23.7
2
70.8
32.6
23.5
3
70.7
32.4
23.5
4
70.5
32.5
23.4
■
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61
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01-02/2013 —
TELE-audiovision International —
全球发行量最大的数字电视杂志
Very good noise performance – signal quality
at the output is almost as good as at the input
Automatic gain control works very well
All Quad outputs are equally good in perfor-
mance
Flat characteristics over the entire UHF fre-
quency band
Suitable for all standards of terrestrial signals:
DTT/DAB/FM
None
Expert Opinion
it, we noticed that the pro-
cessor degrades MER by a
decibel or so. So, perhaps
we could get even a better
result without using the DTT
processor and thus ignoring
GlobalInvacom’s
recom-
mendation? Guess what, we
tried it, but no – the results
were even worse! Admit-
tedly, without the DTT pro-
cessor MER at the input to
the optical system was bet-
ter by 1 dB, but at the same
time MER at the system out-
put was worse by 0.7 dB.
How to explain this un-
expected behaviour? By
removing the DTT proces-
sor we improved one input
parameter (MER) but we
degraded the ratio of use-
ful signals to unwanted sig-
nals including the noise in
the whole terrestrial band.
MER measurement is a nar-
row band technique – only
one transmission channel is
taken into account. It can
not reveal the presence or
absence of the signals or
strong noise in the neigh-
boring channels.
To sum it up, GlobalInva-
com’s new QUAD and QUA-
TRO GTUs in combination
with their ODU32 Optical
transmitter proved to be
high performance compo-
nents oftheir optical dis-
tribution system. Despite
of two signal conversions:
from RF to light and back,
signal quality was affected
minimally while its power
was increased.
To sum it up: GlobalInva-
com’s fibre optic system is
an excellent choice not only
for the distribution of satel-
lite signals but also for com-
bined satellite and terres-
trial signals via one single
fibre optic cable.
Output #
Power
C/N
MER
dBµV
dB
dB
1
80.7
33.9
23.6
2
80.1
34.2
23.5
3
80.1
34.1
23.5
4
80.5
33.8
23.8
Table 3. Results for channel 45 for all four outputs of QUAD GTU.
Table 4. Results for channel 45 for all four outputs of the QUAD
GTU with the presence of satellite signal.
