4-6 | Cyber Hardened IBUC 2, IBUC 2e, IBUC 2G, IBUC R, IBUC G Operations Manual: Operations
To enable ALC,
1. Establish a connection with the Cyber Hardened IBUC 2, IBUC 2e, IBUC 2G,
IBUC R or IBUC G by using either RS232 or SSHv2, described in Chapter 5,
Monitor and Control Features or by the steps provided in Appendix B, Embedded
Web Pages.
2. Set Gain Mode to “Open” via TGC command. See page C-40 for further
description.
3. Set Tx Input and Tx Output Thresholds in order to determine a baseline setting.
See Setting Alarm Thresholds on page 4-4.
4. Change IBUC Tx Output level and monitor it via TPO command, see page C-42,
until it reaches the desired level.
Note:
IBUC Tx Output Level can be adjusted by two methods. The user must either
change the modem output level, or change the IBUC’s internal attenuation level. In
the latter case, use the TPT command, described on page C-43.
5. When the Tx Output Level reading is equal to the level that you want to maintain,
enable ALC via TGC command.
The IBUC will now continuously self-monitor, increasing or decreasing the gain in
order to maintain a constant signal at the level you defined.
Note:
The Tx Output Level is “captured” when ALC is enabled.
AGC
When enabled via TGC command, the Automatic Gain Control (AGC) circuitry in the
IBUC maintains the gain constant and equal to the target gain that was established
when AGC was enabled.
Gain control settings can drift with time or temperature changes. You can reset the
Gain Control function (when reset, the Gain Control returns to mid-range or 0.0).
Terrasat units enable you to offset the target by using the attenuation control without
having to first disable the ALC or AGC.
Example: Set the output power level to 40 dBm and enable ALC. From this point
forward, the ALC algorithm will maintain the output level at 40 dBm.
If you want to change the output level to 41 dBm, reduce the attenuation by 1 dB. The
target level will be updated automatically.
Configuring the External Mute
Pin N of the M&C interface connector has dual functionality: it functions as an alarm
input or an external mute.
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