Seite 58 - TELE-audiovision - Weltweit größte Digital TV Fachzeitschrift

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Channel Number Center Frequency Channel Bandwidth DVB-T ModulationParameters
MHz MHz
41 634 8 8k 64QAM 1/8 3/4
45 666 8 8k 64QAM 1/4 5/6
48 690 8 8k 64QAM 1/8 3/4
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58 TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine — 01-02/2013 —TELE-audiovision.com
quired only if no DC power
is provided from a receiver
via one of the QUAD/QUAT-
RO outputs. Any DC voltage
from 10 V to 20 V is suitable
for GTU. The unit consumes
about 200 mA DC.
Finally, there are two LED
indicators in the GTU: one
for showing the presence
of DC power, the other one
to inform the user that a RF
signal is available at the out-
puts.
The workmanship of the
devices is very good, they
are robust and you should
not have any problems with
the installation if only you
comply with the compre-
hensive “QUAD and QUA-
Closeup of the measurement results at the input (left) and output (right) signal
Table 1. Test signals
TRO GTU Installation Guide”
available from GlobalInva-
com. Among other things,
it also explains how to se-
cure fibre optic cable. This
is probably the most tricky
part for anyone new to fibre
optic cabling, so we advice
you to read it carefully be-
fore the installation.
Before we could meas-
ure the performance of the
GlobalInvacom system with
terrestrial signals we had to
build a test setup. First, we
connected a terrestrial TV
antenna to a DTT headend.
The headend’s job was to
clean the input signal from
unwanted components and
after this to deliver it to the
ODU32 Optical Transmitter.
Since our DTT headend was
able to manage three fre-
quency channels, we start-
ed the test with three DVB-T
multiplexes available in our
location on these TV chan-
nels: 41, 45 and 48. Table 1
lists the parameters of our
test signals. (Table 1.)
We connected the output
of the DTT headend to the
ODU32 Optical Transmitter
and the optical output of the
ODU32 to the optical input
of the QUAD GTU and meas-
ured the signal at the input
and at the output of the op-