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44 45TELE-audiovision International — The World‘s Leading Digital TV Industry Publication — 03-04/2015 — www.TELE-audiovision.com www.TELE-audiovision.com — 03-04/2015 — TELE-audiovision International — 全球发行量最大的数字电视杂志

Global

InvacomGI FibreIRS

O2E

•expands bre optical distribution systems

•improves signal quality at the output

•amplies all 4 bands of a Ku satellite

•replicates the original LNB

TEST REPORT Improving Optical Signals



03-04/2015

www.TELE-audiovision.com/15/03/ globalinvacom

46 TELE-audiovision International — The World‘s Leading Digital TV Industry Publication — 03-04/2015 — www.TELE-audiovision.com

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 wordhere. The basic idea of this

distribution system is a con-

version of the electrical sig-

nals coming off the satellite

to ber 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 bre optic

cables rather than the usual

coax cables. Thanks to the

very low signal attenuation

of bre 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 splitan 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 bre line

end, you use a quad optical-

to-electrical converter, you

The Ideal Amplier known FibreIRS ODU this

system hugely expands the

number of possible outlets

fed by one single bre 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). Thisgives 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 bre 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 bre optic installations.

While 128 outputs fed

by one single LNB alreadyseems 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

http://www.tele-audiovision.com/13/09/spaun

http://www.tele-audiovision.com/13/09/spaun



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48 TELE-audiovision International — The World‘s Leading Digital TV Industry Publication — 03-04/2015 — www.TELE-audiovision.com

signal containg all the tran-

sponders from the original

satellite Ku Band. What can

we do with that?

Those of our readers who

still remember our previous

test reports of GlobalInva-

com products may remem-

ber another of GlobalInva-

com’s products: a dedicated

device converting the whole-band electrical signal to the

optical domain: the GI Fi-

breIRS ODU. Normally, you

would use the GI FibreIRS

ODU along with the above

mentioned LNBm. But if you

want to multiply your distri-

bution system you connect

the GI FibreIRS ODU to the

wholeband output of the GI

FibreIRS O2E. For this pur-

pose, you need a special

short and thick coax cable

because of the high band-

width. At the output of the

GI FibreIRS ODU we get the

optical signal again but much

stronger than at the input of

the GI FibreIRS O2E. We may

say that a combination of the

O2E and the ODU forms a

kind of an optical amplier.

However, it is not an ordi-

nary amplier. An ordinary

amplier would amplify op-

tical signals but could notmaintain the signal quality as

good as in the input. In other

words, we would get a strong

enough signal to be split

again but its carrier-to-noise

or MER would be worse. Not

so here! The combination of

the GI FibreIRS O2E with the

GI FibreIRS ODU does not

just amplify the signal but

regenerates it. It means that

digital errors are corrected

during demodulation and

re-modulation of the signal.

Now, if we connect another

1:32 splitter after combining

the GI FibreIRS O2E with the

GI FibreIRS ODU we can ex-

pect a strong and error free

output signal as in the origi-

nal installation before that

combination.

So far about the theory.

But does it really work like

that in real life? That’s our

job to nd out in the TELE-audiovision test center! So

we collected all necessary

products: we took an opti-

cal LNB (GI FibreMDU), GI

FibreIRS Split32pro, GI Fi-

breIRS O2E, GI FibreIRS

ODU, GI FibreIRS Split16pro

and GI FibreIRS Quad GTU

converter. We connected all

these devices as shown in

the measurement setup cir-

cuit diagram (Fig. 1).

Figure 1 also presents our

optical signal measurement

results. As you can see, the

strong signal at the output

of the optical LNB is attenu-

ated by 16.65 dB when pass-

ing through the 1:32 splitter,

then it is boosted by 16.4

dB after passing the O2E

and ODU combination. So,

in fact, its original strength

is almost exactly recreated

at the output of the ODU.

We decided to split the sig-nal again, this time by a 1:16

splitter and convert it to the

form acceptable for a regu-

lar satellite receiver in the

Quad GTU converter. Would

we have used another 1:32

splitter we would have got-

ten almost exactly the level

of -8.9 dBm which was pre-

sent at the input of the O2E

and ODU combination. So we

may say that combining the

GI FibreIRS O2E and the GI

FibreIRS ODU plus a GI Fi-

breIRS Split32pro will result

Fig. 1 Test setup circuit diagram.



OPINION

EXPERT

+

–

RECOMMENDEDPRODUCT BY

Jacek PawlowskiTest Center

Poland

GI FibreIRS O2EOptical to Electrical Converter

1 2

50 51TELE-audiovision International — The World‘s Leading Digital TV Industry Publication — 03-04/2015 — www.TELE-audiovision.com www.TELE-audiovision.com — 03-04/2015 — TELE-audiovision International — 全球发行量最大的数字电视杂志

in almost exactly 0 dB con-

version gain/loss. In a reallife installation, however, it

makes more sense to use

the 1:16 splitter rst and

the 1:32 splitter second, as

this allows for poorer input

signals.

Please note that for our

test we used quite long -

bres cables: 350 meters in

total and despite of this the

signal strength was practi-

cally unaffected.

So our test set up revealedthat the signal strength was

great but what about signal

quality? Before installing the

test setup as in Figure 1 we

put a regular universal Ku-

Band LNB on a 85 cm dish

and took reference meas-

urements. The dish was

aimed at HOTBIRD on 13°

East. Then, we installed the

optical LNB (GI FibreMDU)

● Very strong and regulated output signal

● Signal quality is even improved due to error correction during

regeneration

● The number of available outputs is multiplied by at least 32

times

● none

1. Testing GlobalInvacom's new GlobalInvacom GI FibreIRS O2E.3 rolls of 100m bre optic cables provide a virtual distributionsystem.

2. This is GlobalInvacom's GI FibreIRS LNB mounted on a smallsatellite dish at TELE-audiovision's Test Center. Up to 32 ofthe new GI FibreIRS O2E could be connected to it, all of themreplicating this one LNB, thus enabling a theoretical endless loopof all identical signal sources - all fed by one single LNB.

and connected it to our test

setup. Finally, we measured

the very last output of the

Quad GTU. Because this was

the same signal as from a

regular universal LNB we

were able to compare the

output of a whole GlobalIn-vacom distribution system

with the output of a regular

good quality universal Ku-

Band LNB – our reference.

The results shown in the

graphs are breathtaking. Not

only the channel power of

all transponders was much

stronger and regulated at 80

dBμV throughout the whole

Ku-Band but also signal

quality, expressed here as

Modulation Error Ratio, im-

proved!

This is something impos-

sible with regular ampliers.

Signal quality will always de-

grade when measured along

a long distribution systemusing analog ampliers. But

the combination of the GI

FibreIRS O2E and the GI Fi-

breIRS ODU is not just an

amplier. The original signal

is regenerated and during

this process digital errors

are detected and xed in a

similar way a diital tv receiv-

er is doing it when process-

ing a transport stream. Am-

plied, regulated and with

removed errors, the signal is

then ready to be split again

by an optical splitter and

sent hundreds of meters fur-

ther through bre optical ca-

bles. And when you convert

it back to the electrical form

at the end of a bre optical

cable, its strength and qual-

ity is better than that meas-

ured directly a regular LNB

output.

What previously has been

seen impossible to achieve:

to re-create the original

source signal after many

splits - has not turned on its

head: the re-created signals

turns out to even be better

than at the source! GlobalIn-

vacom has transformed the

way of distributing (not only)

satellite signals by using the

fbre optic technology. With

the new GI FibreIRS O2E it

is now possible to expand

hugely the number of out-

puts and each of these even

with a better quality than

what the comes out of the

original source LNB.

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