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User manual
c.-Output menu
The first main menu shows the output fre-
quency/channel (depending on the freq.
mode) and the output level.
The output frequency range is 47-862 MHz.
The output level control ranges from 00 to
99.
The Output Format can be:
Norm:
normal output
CW:
only carrier
OFF:
no output
To change the frequency you must press
the
button until is located over the selec-
ted digit. By using
and
modify the value of the digit. The following
decimal values are permitted for the output
frequency:
=> .00 MHz
=> .25 MHz
=> .50 MHz
=> .75 MHz
To modify the output channel, the output
level and the output format you must press
until the cursor is situated over the desi-
red parameter, the value can be modified by
pressing
and
.
To switch between frequency mode and
channel mode see 6.2. MENU EXTENDIDO.
d. Monitor menu
This menu shows the following information:
estimation of the BER (bit error rate before
Viterbi), temperature measurement inside
the module and real QAM baud rate (symbol
rate)
you can
This output rate will depend on the COFDM
input data baud rate and the selected QAM
modulation order.
This data is useful to program an IRD in
which it is needed to know the exact symbol
rate of the QAM modulation.
35
COFDM-QAM
5.2.- EXTENDED MENU
By pressing the
key for more than three
seconds, you can access a series of options
that are less frequently used and that are
called extended menus.
a. COFDM parameters menu
The parameters of the COFDM transmission
are displayed in this menu:
- FFT size (number of carriers): 8K-2K.
- Constellation (type of modulation):
QPSK - 16 QAM - 64QAM.
- Guard interval: 1/4, 1/8, 1/16 o 1/32
- Viterbi rate (coderate): 1/2, 2/3, 3/4, 5/6
o 7/8.
If the QAM modulator is unlocked the follo-
wing screen will be shown.
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