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TELE-audiovision International — The World‘s Leading Digital TV Industry Publication

— 03-04/2015

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TELE-audiovision.com

every individual carrier of the

selected transponder. What’s

the point of finding out those

figures? As a matter of fact,

conventional measurements

often cannot identify prob-

lems with DVB-T/T2 trans-

mission. The MER appears

to be perfectly okay and the

constellation diagram indi-

cates no issues at all, even

though reception is impaired,

some elements of the video

are showing artefacts or – if

worse comes to worst – the

video drops out altogether

every once in a while. So

what’s wrong with the signal?

The UHF/VHF frequency

bands are pretty crowded

these days, as they are not

only the domain of DVB-T/

T2 signals but also of a num-

ber of additional services and

transmissions. Since those

other transmission gener-

ally can only use a narrow

bandwidth when compared

to TV transponders, it hap-

pens ever so often that they

don’t interfere with the entire

transponder, but only with

individual carriers on a tran-

sponder. Conventional MER

measurements, on the other

hand, can only give out the

average error rate of all car-

riers on a transponder. This

way technicians have no way

of finding out that only some

carriers of the many that are

available experience inter-

ference due to some exter-

nal narrow-bandwidth signal

source. And since the entire

stream is made up of all those

individual carriers, we arrive

at the unsatisfactory situa-

tion outlined above.

It is exactly here that the

Spaun Sparos 711 has an ace

up its sleeve with the MER

vs. carrier measurement,

as it allows identifying hid-

den issues. We expect that

targeted measurements like

MER vs. carrier will only rise

in importance, because there

is one relatively new service

in particular that causes nar-

row-bandwidth interference:

LTE – three letters that can

have a major impact. Expe-

rience shows that LTE does

not only affect dedicated LTE

frequencies but also many

neighbouring

frequencies.

Thanks to the Spaun Sparos

711 and its MER vs. carrier

measurement such interfer-

ence cannot only be identified

quickly and reliably, but it can

also be determined whether

and to what extend an LTE

filter could improve the situ-

ation.

As professional installers,

we would never want to do

without echo and MER vs.

carrier measurements for

DVB-T/T2 again, and thank-

fully Spaun has equipped

its new flagship meter with

this state-of-the-art option.

What’s more, those measure-

ment types are not only avail-

able, but also implemented in

a very user-friendly way and

with high resolution. Thanks

to the built-in MPEG-2/4 de-

coder all free-to-air channels

can be displayed as well. If

you also want to see encrypt-

ed channels – in addition to

analysing them – you may

use the integrated card read-

er we have dealt with above.

Activating the ASI input in

TV mode is another interest-

ing option. This basically turns

the Spaun Sparos 711 into an

ASI monitor that can be used

to check whether profes-

sional receivers, modulators,

multiplexers, etc. work as in-

tended and whether a correct

and usable signal is available.

With this bonus feature the

Spaun Sparos 711 becomes

the perfect meter for cable

head-ends and broadcasters

as well.

As mentioned above, the

ASI output is always active

and provides the current

transport stream, which is

very helpful for documenta-

tion purposes but can also

be extremely useful when it

comes to generating an ASI

signal for a head-end.

There’s another brilliant

feature implemented in the

Spaun Sparos 711 that al-

lows recording the currently

selected channel onto an ex-

ternal USB storage medium.

This file can then be used to

have an in-depth look at the

MPEG signal on your PC and

to perform additional meas-

urements. We did notice,

however, that only the stream

that is received from the

MPEG decoder is saved, rath-

er than the entire transport

stream. While this is a bit of

a drawback, we can confirm

that the recorded individual

stream comes with all audio

Automatic

measurement

protocols are a

great aid. Here we

are seen measuring

the wall outlets in

a home to identify

potential problems

with either the

outlets or the cable.

We repeat the same job in

a different home. Measuring

all of the 36 DVB-C

transponders on two wall

outlets only took 5 minutes.