TELE-audiovision - Weltweit größte Digital TV Fachzeitschrift - page 72

TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine
— 07-08/2014
sired signals.
The company ROKS took the MITRIS
system and expanded it marketing it
under the name MITRIS-CS; the CS
stands for Cellular Structure and refers
to the ability to operate any number of
relay stations.
Implementation is ingeniously sim-
ple: the transmission system, in which
the incoming TV signals are combined
via a multiplexer, optionally encrypted
with a DVB scrambler and finally modu-
lated to DVB-S/S2, functions exactly
the same as in any satellite station ex-
cept with MITRIS-CS the signal is not
uplinked to a satellite in geostationary
orbit, rather, the signal is broadcasted
terrestrially using omni-directional an-
The end user receives these signals
with a standard satellite system includ-
ing a satellite antenna that is instead
pointed horizontally at the provider‘s
transmission antennas.
In other words, it‘s pointed to a trans-
mission antenna mast instead of up to
a satellite. There‘s only one restriction
and it‘s the same restriction you would
have with normal satellite reception:
there must be a clear line-of-sight view
between the transmission and receiv-
ing antennas.
If this is not the case or if a larger
region needs to be covered, relay sta-
tions can be utilized with MITRIS-CS.
Through specially developed ROKS di-
rectional antennas additional transmis-
sion towers can be supplied with the
MITRIS-CS signal which would then re-
transmit the signal to end-users using
omni-directional antennas.
In order for this to work, two differ-
ent frequency bands must be used,
each with 800 MHz bandwidth: one for
the directional antenna and at the same
time the other for the omni-directional
antenna. If both of the transmissions
were in the same frequency band, the
differing transmission times would lead
to significant interference similar to
the all-too-familiar echoes in DVB-T/T2
SFNs (Single Frequency Networks).
Since the Ku-band already utilizes two
frequency bands (Low Band: 10.7-11.5
GHz and High Band 11.7-12.5 GHz), it
made sense for ROKS to use it also for
their MITRIS-CS. The Low Band is used
for the relay stations while the High
Band is used by the end-users. Why?
It‘s very simple: the lower the fre-
quency the further the transmission
propagation at the same output power.
It‘s for this reason that ROKS uses
the lower frequency band for their di-
rectional antennas while the end users
utilize reception systems with the 22
kHz switching signal turned on in the
High Band. The LNBs ROKS distributes
actually are for the high-band only.
Calculations show that MITRIS-CS is
the most cost-effective way to broad-
cast TV content: if you consider both
the costs to build the infrastructure
and operate the system, the result is
the lowest price per channel. This type
of system is also advantageous for end
users since they would be able to use
standard satellite systems for recep-
How do you build such a MITRIS-
CS system? ROKS, the inventor of the
MITRIS-CS system, was founded in
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