FIELD METERS MCT 080 / 081 / 082 / 085 USER MANUAL
p.
92
Reminder :
Remember: In terrestrial TV broadcasting, the received signal on the antenna comes from several possible
ways: the
echoes
.
In digital TV DVB-T/H and DVB-T2, these echoes may help or degrade the image according to the time
delay between the various signals that reach the antenna.
The broadcasting norms DVB-T and DVB-T2 define a modulation parameter called "
guard interval
" where
echoes won't disturb the reception.
The transmission of digital data (
Symbol
) is interrupted during the
guard interval
.
A delayed (or advanced) symbol of any
shorter
duration than the guard interval will not disturb the reception.
A delayed (or advanced) symbol of any
longer
duration than the guard interval will disturb the reception.
You have to reduce the level of reception of the echoes by orienting the antenna or by selecting a more
directive antenna.
The
Echo
function of the appliance enables you to display possible
echoes
that disturb the received signal.
Guard interval
limit
Main signal
Pre-echo
Echoes out off
the guard
interval
Measurements
form arrow
position