Fracarro SAF-HD 10 Notice D'utilisation page 25

From the analysis of the above graphs, three fundamental cases can be distinguished:
1. Proper operation level.
If the terrestrial channel input is within the foreseen range, the AGC circuit works properly.
2. Low operation level.
This occurs when the input signal level on the selective programmable module is lower than the level
indicated in the technical specifications. The programming menu will display "LOW IN LEVEL" and the
module will return the output to a signal with a level that is proportionally lower than the maximum value
of the specification.
3. Operation level under overload (or saturation).
This occurs when the input signal level on the selective programmable modules is higher than the level
indicated in the technical specifications. The module will return the output to a signal level that is propor-
tionally higher than the minimum value of the specification.
4.3 WARNINGS FOR FILTERING AND CHANNEL CONVERSION
For the correct operation of the SAF-HD headend, the input signals should respect the following conditions:
1. Input signal level: 50 ÷ 73dBμV
The input level of the signals to filter must be between 50 and 73dBμV for CAG to work correctly.
2. Overall input power: 90 dBμV
This condition is met if all channels satisfy the previous item (level not higher than 73dB).
If the overall input power is more than 90dB, the input signal must be attenuated.
3. Max difference of the level among the filtered channels: 20dB
To avoid intermodulation, it is recommended that there is no filtering for channels that have a difference of
20dB between them. For the adjacent channels, we recommend not filtering channels that have a differ-
ence of more than 15 dB with the adjacent channel.
NOTE:
To optimize the performances of the SAF-HD unit, in the event of important differences among the channels
within the antenna, refer to the following examples:
BLU420F
DE1-10
Low level TV
channels management
IN 1
To the network
It is suggested to use two different RF inputs: one for low RF signal reception and one for high RF signal
reception.
ANT1200A
High level TV
channels
management
IN 2 IN 3 FM
SAF
SAF
BLU920F
BLU220F
High level TV
channels management
IN 1 IN 2
SAF
To the network
25
Low level TV
ANT1200A
channels
management
IN 3 FM
SAF