Terrasat IBUC 3, Руководство по эксплуатации

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4-6
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IBUC
3
, IBUC
3 G
Operations Manual: Operations
Engineered to Endure
2. With the Gain Mode set to “Open” and the Tx Input and Tx Output Thresholds set,
monitor the Tx Output level in order to determine a baseline setting.
3. When the Tx Output Level reading is equal to the level that you want to maintain,
enable ALC by setting the Gain Mode to “ALC”.
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.
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.
AGC
When enabled, 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 by applying the following steps:
1. Change the Gain mode to Open Loop
2. Reset Gain Control
3. Readjust the Target Gain
4. Change the Gain mode back to AGC
Terrasat units enable you to offset the target by using the attenuation control without
having to first disable the ALC or AGC.
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.
External Mute
When the IBUC operates as a single thread IBUC, Pin N of the M&C interface
connector functions as an external mute. If it is not connected (left open), then
transmission is not muted. When Pin N is connected to Pin F (chassis ground),
transmission is muted.