Background Image
Previous Page  73 / 164 Next Page
Show Menu
Previous Page 73 / 164 Next Page
Page Background







05-06/2015 —

TELE-audiovision International —


7. First test: modulating a DVB-C

transponder with 256-QAM at 354 MHz.

8. The transponder generated by the DTA-

2115 is clearly visible in the spectrum.

9. The field meter shows the corresponding

constellation diagram, the signal is locked

with no problem. This is nice to test a

receiver or to analyse the content, however,

the signal is unrealistically good.

10. DekTec allows to control the SNR of the

signal. Introducing a random background

noise will produce a more realistic

constellation and gives the tuner some


11. The field meter can still lock onto the

signal, but now the bit error correction has

some work to do.

12. Second test: modulating a DVB-T2

transponder with 256-QAM and rotated

constellation. StreamXpress offers a

whole window with access to practically all

parameters for DVB-T2. Thankfully DekTec

included useful default settings.

13. The field meter could lock to the signal

without any problem. The result is a perfect

tilted constellation diagram.

14. This constellation diagram looks more

realistic… I activated the SNR functionality

on the StreamXpress software. Notice the

slightly lower MER.

15. DVB-T2 does not necessarily use a

rotated constellation. On the advanced

DVB-T2 settings panel you can turn this off.

16. Here we see the resulting DVB-T2

constellation diagram without rotation.

17. To test error handling, the

StreamXpress software allows to introduce

errors. This can come in very handy, when

error correction algorithms need to be


18. Another test: generating a DVB-H

transponder. I do not receive such signal in

my location, so it is good to be able to rely

on the DTA-2115 to obtain such a signal,

when DVB-H receivers have to be tested.

19. Any modulation can be generated. To

test this, I modulated a DVB-S2 8-PSK

signal at the unusual frequency of 456 MHz.

20. The field meter shows the generated

transponder on the spectrum. I don’t have

a suitable receiver to demodulate this

transponder, but this shows how R&D

departments could explore new frequency

and modulation combinations.

facturing process, special

software could be developed

that at the touch of a button

could play back one tran-

sponder stream after anoth-

er at different frequencies.

The technician would not

need to do anything special

in the StreamXpress soft-

ware and there would not

be any mistakes that would

have come from entering

wrong frequency informa-

tion. Even though we‘re not

professional programmers

here in the test lab, we were

easily able to create test

software like this in a short

amount of time. This shows

how the well-thought out

DekTec concept offers un-

limited possibilities. Thanks

to the open and documented

API, the new DTA-2115 can

also, as expected, be inte-

grated into user-defined ap-


Whether it‘s in R&D de-

partments, in service cent-

ers or at trade shows, if

you‘ve worked with a DekTec

modulator once, you‘ll never

want to do without it again.

With the DTA-2115, we‘re

talking about an unbeliev-

able product that can work

with any modulation and in

every standard frequency


The card works as ex-

pected. Working with the

StreamXpress software is

logical and uncomplicated.

Naturally, complex modula-

tions such as DVB-T2 come

with an array of parameters

yet the presettings are rea-

sonable and if you need to

test a signal like this, you

would already know which

parameters would need to

be tweaked.

We love the new DTA-2115

and highly recommend its

use in stationary worksta-