Harmonic HRR 4104, Product Manual

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Understanding the AGC Function
HRR 4104 Return Path Receiver Product Manual Rev A (3/05) 4–3
4.1.8 Manual RF Pad Value
If AGC is disabled, you can set the actual pad value (in dB) to control the
output power.
4.1.9 Default Adjustment Values
At initial power up, default values are set as shown in Table 4-1. Once these
values have been changed, the new settings are retained, even after the power
has been shut off.
4.2 Understanding the AGC Function
This section describes some details of the AGC function of the HRR 4104.
The following example will help you when you set up the receiver by
following the setup instructions in Section 4.3 or 4.4:
1. At initial power up, AGC is disabled.
2. Once the fibers are connected and a reference optical input power is
established, in the Receiver Adjust menu, set the manual RF pad to the
value that generates the RF output you are looking for.
- Example: Given the optical input power of the link (for example,
–8 dBm), the RF pad value that generates the appropriate RF output for
your link is 13 dB.
3. Enable AGC via the Receiver Adjust menu.
- With the example above, the module sets the following parameters as
default values:
AGC Optical Setpoint = –8 dBm
AGC Pad Setpoint = 13 dB
- You will be able to go back and look at these AGC settings via the
Receiver Diagnostics menu, and you can adjust them via the Receiver
Adjustments menu (see Section 3.1.3).
- The module adjusts the RF pad value automatically to compensate for
changes in optical input power.
Table 4-1: Factory Default Settings
Adjustment Value
Optical Alarm Limit –18 dB
Input Wavelength 1310 nm
Mute Unforced
AGC Mode Disabled
Manual RF Pad Value 10 dB