Cisco Cisco 1 GHz GainMaker Amplifier Guía De Instalación
Chapter 3 Balancing and Setup
66
To Set the Output Level for a Cold Amplifier
After setting the tilt, complete the following steps to select the proper pad values for
the amplifier. The output level of the amplifier is set by selecting the proper pad
value.
the amplifier. The output level of the amplifier is set by selecting the proper pad
value.
Note: Using this procedure will result in a more accurate output level setting when
balancing an amplifier using amplifier and coax compensation mode if the amplifier
has had little or no warm-up period.
balancing an amplifier using amplifier and coax compensation mode if the amplifier
has had little or no warm-up period.
Important: For the most accurate output level setting, allow the amplifier to warm up
for approximately one hour and use the To Set the Output Level for a Warm
Amplifier procedure above.
1 Connect the test probe to the forward output test point.
2 Measure the output level at the highest design frequency, and compare this level
for approximately one hour and use the To Set the Output Level for a Warm
Amplifier procedure above.
1 Connect the test probe to the forward output test point.
2 Measure the output level at the highest design frequency, and compare this level
with the design level (on the design print), minus 1 dB.
The station output level must be 1 dB lower than the output level specified by the
design print. This reduction in output level will be offset by an increase in internal
amplifier gain as the thermal circuit in the amplifier warms up.
design print. This reduction in output level will be offset by an increase in internal
amplifier gain as the thermal circuit in the amplifier warms up.
3 Is the measured output level within ±0.5 dB of the design level minus 1 dB?
If the output level is within ±0.5 dB of the design output level minus 1 dB,
proceed to step 5.
proceed to step 5.
If the output level is more than the design output level minus 1 dB, replace the
forward input pad with a higher value pad.
forward input pad with a higher value pad.
If the output level is less than the design level minus 1 dB, replace the forward
input pad with a lower value pad.
input pad with a lower value pad.
4 Repeat steps 2 and 3 until the output level is correct.
5 Proceed to Balancing the Reverse Path (on page 68).
5 Proceed to Balancing the Reverse Path (on page 68).
Note: On the High Gain Dual, the type of plug-in signal director installed directly
affects the signal level measured at the Aux RF output test points. This is because the
Aux RF output test points are located after the signal director in the forward RF signal
path. The test points now reflect the actual output of the port.
affects the signal level measured at the Aux RF output test points. This is because the
Aux RF output test points are located after the signal director in the forward RF signal
path. The test points now reflect the actual output of the port.
It is important to determine if the Aux output level specified on the design print is the
level before or after the signal director.
level before or after the signal director.
If it is the level after the signal director (port output level), the test point should
match the print design level.
match the print design level.
If it is the level before the signal director, the test point level should be “x” dB
lower than the print design level, where “x” is the insertion loss of the signal
director feeding the particular Aux port being balanced.
lower than the print design level, where “x” is the insertion loss of the signal
director feeding the particular Aux port being balanced.
Forward Path Balancing Using Trim Networks
This section describes the procedure to follow when installing a trim network.