- 26 -
HDTA 614 T ASI
—> The "Transmission parameters" – "
COFDM-MODE
" submenu is acti-
vated.
t
r ansmission
Par a meters
In this menu you can set the code rate and the guard interval.
COFDM–MODE
G1/32
Bx 4A
!
2k C7/8
—> The 2k transmission mode is fixed.
2k mode: 1512 carrier for user data (total 1705 carriers)
—> A displayed "!" indicates an output data rate overflow (page 40).
COFDM–MODE
Bx 4A
!
Code rate
During a transmission, data can be lost or changed. To recover this data, redun-
dancy is added to the signal to be transmitted (forward error correction). 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…
".
• Set the guard interval required using the
buttons ("
G1/4
", "
G1/8
",
"
G1/16
", "
G1/32
").
• Press the
button.
