Advantech AMT-70, Installation And Operation Manual, Page: 41 / 160

AMT-70/AMT-73/AMT-75 Installation and Operation
2.6.2
External Clock Reference (MIL-STD-188-115)
The rear panel includes a BNC connector (J14) for connection to an External 5 MHz Clock. When
activated, all frequencies generated within the modem exhibit the same accuracy and stability as this
reference.
2.7
RF/IF Interfaces
2.7.1
Modulator L-Band Output (AMT-70L)
The L-Band output signal is presented on J6 (Type N female, 50
Ω
) on the rear panel of the modem. If
the modem has been ordered with the BUC power option then the DC voltage is switched onto the
inner conductor of this connector. When installing the modem to the system, BUC power should be
turned off.
The following commands are available via the Command Line Interface for the BUC control.
Command Arguments Description
BUCPOWER
OFF, ON BUC Power ON/OFF
BUC
Monitor the BUC voltage used
BUCI
Monitor the BUC current used
Figure 4: BUC Control Commands
2.7.2
Modulator L Band Output (AMT-73L)
The L-Band output signal is presented on J1 (Type TNC female, 50
Ω
) on the rear panel of the modem.
There are currently no provisions for providing power to the BUC or SSPB.
2.7.3
Demodulator L Band Input (AMT-70L and 75)
The demodulators on all AMT-70L modems are capable of being used in conjunction with most C-band
or Ku-band LNBs or BDCs, with L-Band IF frequencies in the range of 950-2150 MHz. For L-Band
operation, modem has two separate L-Band inputs and a separate L-Band N-Type output, accessed at
the rear of the unit.
There are two inputs to demodulator, useful for receiving from two different polarizations or two
different satellites. One is on J1 (Type F female, 75
Ω ), and the other is on J2 (Type F female, 75 Ω ).
Either can be connected directly to the Receive IF connector of the appropriate LNB/BDC. The cable
loss should be considered when selecting the cable. The demodulator can additionally provide DC
power (+13/+18 V, 0.4 A), a 22 kHz tone or a 10 MHz reference on the same cable as the L-Band
receive carrier. The ON/OFF state of the LNB power is indicated by an LED on the Front Panel
.
41
CAUTION:
With BUC power enabled, there is a potentially damaging DC voltage applied to the
modulator output. When connecting test equipment, or a local modulator (or any DC
coupled devices), always use appropriate DC blocks, and disable BUC powering.