TANDBERG TT-1222, Reference Manual

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Reference Guide: TT1222 4:2:0 Professional receiver Page 3-5
ST.RE.TT1222.2
CAUTIONS…
1. The Receiver provides dc power via the active L-band input connector to drive an LNB (Low Noise
Block Down-Converter). Do not connect equipment other than an LNB to this connector. Failure to
do this may result in damage to the external equipment
2. The F-type connector is not suitable for repeated connection and disconnection. When intended for
use in this way, fit a sacrificial connector and connect to it.
Use of an Attenuator
The L-band input can be connected via a suitable attenuator to give
adequate consideration to lightning and surge protection.
In most cases an attenuator will not be required. The following list
summarises the circumstances in which one should be used.
1. If the wanted input level is greater than the specified maximum
permissible (-25 dBm)
2. If the downlead is a short length of low-loss cable and the LNB in use
has a poor return loss (7 dB min)
3. If the receiver is receiving one of many carriers in a multi-carrier FDM
system and the level of the wanted signal is close to the specified
maximum permissible
Setting Up the QPSK Input
Setting up the QPSK input is done entirely from the
SETUP
⇒
INPUTS
menu.
Table 3.4 steps through all the necessary settings to achieve signal lock.
Table 3.4: Tuning the Satellite Receiver
Step Action Result
1. Go to the input menu, located under the setup
menu. The display will read “SET: INPUT” on the top line.
2. Repeat pressing the up arrow, until you are on the
top line The display will read “LNB Freq.:” on the bottom line.
3. Press right once, and then by using the arrow
keys as explained in Chapter 4, enter the desired
LNB frequency. The LNB frequency should be set to match your external
LNB.
4. Go down one line, and edit the satellite channel
frequency
1 .
This sets up the tuning frequency in the receiver.
5.
Go down to the next line, and enter the Symbol
rate.
This sets up the incoming symbol rate of the demodulator.
6. Continue on-line down to the Inner Code rate,
select the correct inner code. This sets up the Forward error correction (FEC) rate of the
demodulator.
7. For the final three items, select the correct LNB
voltage, and turn 22 kHz control signal and
spectrum inversion on or off. This finalises the set-up of the satellite demodulator. Next
to the menu name (SET:INPUT), status information about
the signal lock is being displayed. (Signal strength.)
1 The satellite frequency should be within the area of the LNB frequency (±950 to 2150 MHz). If your frequency is
outside this range, replace your LNB with a higher or lower ranging unit.