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QMultiFlex-400™ Installation and Operating Handbook
6.2.4.10 Tx Frame Size
Short
Normal
6.2.4.11 Tx Frequency Band
The modem supports independent selection of IF and L-band operation in transmit and
receive. This menu option controls the transmit frequency band.
IF
L-band
6.2.4.12 Tx Carrier Frequency
There are various Tx frequency control options, depending on whether IF or L-band has
been selected and whether a BUC is fitted that is being controlled via the modem. The
frequency control options are presented in Tables 6-9 through 6-11.
Range:
50.0MHz to 180.0MHz; step size: 0.0001MHz (i.e. 100Hz)
Description:
This is the IF frequency used in transmitting to satellite. Note that values
between 90MHz and 100MHz cannot be selected.
Range:
950.0MHz to 2450.0MHz; step size: 0.0001MHz (i.e. 100Hz)
Description:
This is the L-band frequency used in transmitting to satellite.
If the BUC LO frequency has been set on the Edit->Service->BUC menu
then the L-band transmit frequency will no longer be available and will be
automatically controlled by the modem to achieve the requested BUC
transmit frequency.
This represents a frame size of 16,200 bits per frame.
This represents a frame size of 64,800 bits per frame. This is more
bandwidth efficient than short frames but has four times the
latency. As a guideline, short frames have a latency of around
25ms at 1Mbps, whereas the latency for normal frames is around
100ms at 1Mbps. The latency will halve as data rate doubles.
Table 6-7 Tx Frame Size
This selects the 70MHz and 140MHz IF bands, allowing operation
from 50MHz to 90MHz and 100MHz to 180MHz.
This selects L-band, allowing operation from 950MHz to
2450MHz.
Table 6-8 Tx Frequency Band
Table 6-9 Tx Carrier Frequency (IF)
Table 6-10 Tx Carrier Frequency (L-band)
6-15
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