
- 31 -
HDE 400
—> The "Transmission parameters" – "
COFDM-MODE
" submenu is acti-
vated.
t
r ansmission
Par a meters
—> This menu is only be displayed if "COFDM modulation" is selected
in menu "RF output" (page 23)!
If "QAM modulation" is selected please continue with submenu "Sub-
stitute signal in the case of an incorrect input signal" – "
FAILURE
"
In this menu you can set the code rate and the guard interval.
Bx 2
2k C7/8
COFDM
G1/32
—> The 2k transmission mode is fixed.
2k mode: 1512 carrier for user data (total 1705 carriers)
Code rate
During a transmission data can be lost or changed. To recover this data, a re-
dundancy is added to the signal which is to be transmitted (forward error correc-
tion). The factor of the quantity of redundancy contained in the bits transmitted is
called code rate.
Using the setting "
C7/8
" you can get the highest output data rate at lowest re-
dundancy.
• Use the
buttons to place the cursor under "
C…
".
• Set the code rate required using the
buttons ("
C1/2
", "
C2/3
",
"
C3/4
", "
C5/6
", "
C7/8
").
Guard interval
In this menu item you set the relation of the duration of the user symbols to the
duration of the guard intervals to be transmitted. A high guard interval, e.g.
"
G1/4
" causes a low output data rate. For cable networks the setting "
G1/32
"
is adequate.
• Use the
buttons to place the cursor under "
G…
".
Содержание HDE 400
Страница 1: ...Assembly Instruction HDE 400 ...