Terrasat IBUC 3, Operation Manual

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2-14
|
IBUC
3
, IBUC
3 G
Operations Manual: Functional Description
Engineered to Endure
Certain considerations must be made when selecting the IFL because appropriate
shielding and signal levels are required for normal system operation. The IBUC
3
and
IBUC
3 G
are designed to operate with a - 30 dBm Tx L-band input signal to achieve
rated power at maximum gain/minimum attenuation. Both IBUC
3
and IBUC
3 G
provide a variable attenuator that is accessible through the various M&C interfaces
that enables the gain of the unit to be reduced by up to 30 dB in 0.1 dB steps. The
attenuator can be used to prevent overdrive to the IBUC in configurations with a short
cable run (or IFL), thus preserving the dynamic range of the modem. In addition, the
externally referenced IBUC and the externally referenced LNB must have a 10 MHz
input signal at +5 dBm to - 12 dBm for the IBUC, and 0 dB to - 10 dBm for the LNB.
The maximum voltage drop for a 24 VDC IBUC is 4 volts and the maximum drop for
a 48 VDC IBUC is 11 volts.
Note:
The system configurations in Figure 2.4 to Figure 2.5 depict an external 10 MHz
reference signal; however, an optional internal 10 MHz reference signal is available.