GUIDE TO INSTALLATION AND OPERATION
Frequency
Selected:
Nominal frequency for the channel. This
value is calculated from the carrier’s published
frequency for the desired service on the satellite, and
the conversion factor for the LNB (Low Noise Block)
downconverter that is in use, and entered into this panel
manually (NB. see section on Presets below).
Actual:
This window shows the actual frequency
detected by the tuner
Scan Range:
Use the pulldown to select a scan range
around the selected value
Options: 1 MHz, 2 MHz, 3 MHz, …., 9 MHz, 10 MHz.
Symbol Rate
Selected:
enter the data provided by the carrier
Actual:
measured
value at the IRD-3111
Code Rate / FEC
It is necessary to specify the overhead dedicated to
forward error correction.
Selected:
Use the pulldown to manually enter the value
specified by the satellite signal provider. In the case of
DVB-S, the value can be recovered from the signal, so an Auto detect mode is provided.
•
In DVB-S mode:
[Auto, 1/2, 2/3, 3/4., 5/6, 7/8]
•
In DVB-S2 mode:
[1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10]
Actual:
DVB-S mode only – shows the current value; useful in Auto mode.
Roll Off:
spectral band shaping characteristics. Bandwidth = (1 + Roll-off factor) * symbol rate
DVB-S mode:
0.35
DVB-S2 mode:
[0.20, 0.25, 0.35]
Spectral Inversion:
If the L.O. of the LNB downconverter is higher than the satellite downlink frequency, the
downconverted spectrum will be inverted, and must be re-inverted in the tuner.
[Not Inverted, Inverted, Automatic]
DVB-S2 Pilot:
The pilot tone may be included in the DVB-S2 signal, and detecting it may be required for locking on to
the signal. Not available in DVB-S mode. Use the radio buttons to turn pilot detection ON or OFF.
LNB Control Settings:
The Low Noise Block downconverter can output four different bands of signals extracted from the incoming
satellite signal. Only one can occupy the bandwidth available on a coaxial cable, so a selection process is
required. The selection mechanism employed can be used to switch the output of an LNB equipped with a single
output among the four possible bands, or select among the four available outputs of a 4-output LNB to choose the
input to the IRD-3111’s tuner using an outboard switching arrangement. The switching signal uses two methods:
•
DC voltage applied to the tuner end of the cable (13 V or 18V) – selects the polarization
Note: the IRD-3111 may not supply enough power to operate an LNB directly – the LNB supply current is
limited to 80 mA – which case the voltage from the IRD-3111 should be used to trigger an external driver that
switches the LNB.
•
A 22 KHz tone sent to the LNB from the IRD-3111 – selects the frequency band.
Figure 3.5 Tuner DVB-S2 panel
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| IRD-3111