AMT-70/AMT-73/AMT-75 Installation and Operation
8.14 Alarms Connector Description
The modem provides 3 Form-C contact (relay) outputs for FAULT indication on the Modulator board
which includes a FAULT from the Demodulator board (P5 - AMT-70, J6 - AMT-73L). One alarm
relay set is undefined. The provided signals are as follows:
Figure 56: Pin-outs for alarm connector
Pin No. SIGNAL DESCRIPTION
1 (Undefined) Relay 1 NO
2 (Undefined) Relay 1 NC
3 Demodulator Fault Common
4 Modulator Fault NO
5 Modulator Fault NC
6-8 N/C (not connected)
9 (Undefined) Relay 1 Common
10 Demodulator Fault NO
11 Demodulator Fault NC
12 Modulator Fault Common
13-15 N/C (not connected)
The Modulator alarm will activate for the following conditions:
• AC Power Fail
• ASI Input Failure due to;
o MPEG Sync Marks not correct
o ASI frequency outside +
o ASI signal not present
500ppm tolerance
The Demodulator alarm will activate for the following conditions:
• Demodulator communications not responding
There are many types of coaxial cables that can be used to connect the LNB/BDC to the
demodulator input. The appropriate cable is dependent on many factors, including the gain in the
LNB and BDC/LNA, and the distance between the LNB or BDC and the input to the demodulator.
The cable and its connectors should have impedance of 75 Ω. One such cable is the 5916 or 5916R
cable supplied by CommScope. It is an RG11 type cable that has an RF loss of 4.4 dB @ 950 MHz
and 6.33 dB @ 2150 MHz per 100 ft, and a DC resistance of 1.5 Ω per 100 ft. Connectors for this
cable are available from Gilbert Engineering.
• Demodulator lost of any Timing, Carrier, or FEC Lock
8.15 L-Band Transmit Cable
The recommended cable used to connect the modulator output to the BUC is available from Times
Microwave Systems. The part number of the bulk cable is LMR-600DB. The assembly number of a
finished cable is AE50520-XXX where XXX specifies the cable length in feet. This cable has male
type-N connectors at each end. The cable and its connectors have an impedance of 50 Ω.
114
8.16 L-Band Receive Cable
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General