| Introduction |
| Individual Antennas |
I.C.T. -Common Infrastructure of Telecommunication:
What is a ICT project?
A ICT projects is a project of technical character that describes the necessary installations needed and their requirements for the
adjustment of the new promotions to the services of Telecommunication.
Levels at the user tap according to ICT:
The channels of the network of unique frequency correspond to channels 66 to 69, except in border zones that these channels are different.
Comparison with the analogical terrestrial TV:
The following picture summarizes the differences between analogical and digital terrestrial signals.
| Standard | Modulation | Level | C/N | BER |
| PAL B/G | AM | 57-80 dBµV | >43dB | - |
| DVB-T | COFDM 8K 64QAM | 45-70 dBµV | >25dB | <9x10E-5 |
Characteristics of the signal in the tap:
The following picture displays the values that terrestrial digital TV signals must have in the tap.
| TAP CHARACTERISTICS | |
| LEVEL | 45-70 dBµV |
| C/N | >25 dB |
| BER | <9x10E-5 |
They correspond at the quality levels similar to the indicated in ICT installations. The measures of these values can be made with the following equipment:
| MESURE | |
| Level | TV SATELLITE ANALYSER OR RECEIVER TDT |
| C/N | TV SATELLITE ANALYSER |
| BER | TV SATELLITE ANALYSER OR RECEIVER TDT |
The measurement of relation carrying of noise will be correct if is measured with a TV & satellite analyser for digital signal.
The Ber measurement we can make it with the receiver of terrestrial digital TV or with a TV & satellite analyser equipped with BER measures in COFDM.
Adjustment of the head signal:
The digital signal and analogical are distributed in the same band, therefore it has similar characteristics of noise and attenuation in all the
distribution. The levels of the DS in relation to the analogical signal comes given by the difference demanded levels in the tap.
Let see the following comparative picture:
| SISTEM | HEAD LEVEL | LEVEL TAP | C/N |
| ANALÓGICO | 57-80 dBµV | >43-66 dB | |
| DIGITAL | -10 dB | 47-70 dBµV | >33-56 dB |
| -15 dB | 42-65 dBµV | >28-51 dB |
The DS must be fit to a level between 10 and 15 dB lees than the analogical signal.
This way we will guarantee that the tap levels are correct and also the carrying relation of noise.
In any case is recommended to verify in tap that they are fulfilled the requirements previously indicated.
Next a general scheme of an
ICT:
Photographies of work made -
ICT:
Telect ®
1-RITU. Unique Infrastructura Registry Telecommunication.
2- Electric Box necessary in the telecommunications registers, in the
top one and the inferior.
3- R.S. - Secundary Register.
4- Upper Canalitzation and linking.
5- P.A.U. - User acces point.
6- Antenna of the installation.
Telect
Company of Telecommunications
Llagostera (Girona) Spain
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