Chapter 3, Description of Screens

Adjacent Channel Power Screen

How the Test Set Measures Adjacent Channel Power (ACP)

When you access this screen, the Test Set automatically starts a multi-step process for measuring ACP:

1.AF Generator 1 is turned off if the Carrier Ref field is set to Unmod.

2.The amplitude of the center frequency (Tune Freq) is measured to establish a refer- ence.

3.AF Generator 1 is turned back on if it was previously turned off.

4.The power in each of the adjacent channels is analyzed.

5.Adjacent Channel Power is calculated and displayed. This value can be displayed as an absolute power level or as a ratio referenced to the center frequency’s level.

NOTE:

Which Input Port to Use. The TX Power measurement is used to calculate absolute Adjacent

 

Channel Power. Since TX Power can only be measured using the RF IN/OUT port, you must

 

use this port to measure ACP Level. ACP Ratio can be measured using either the RF IN/OUT

 

or the ANT IN port.

 

Measuring ACP on AM Transmitters. When measuring AM signals, the reference level

 

must be measured on an unmodulated carrier; so the Carrier Ref field must be set to

 

Unmod. After the reference is measured, the power in the adjacent channels must be measured

 

with modulation. This requires the modulating signal to be turned off and on repeatedly as

 

measurements are being calculated and displayed. Since the Test Set automatically turns

 

AFGen1 on and off when the Carrier Ref field is set to Unmod, you must use AFGen1

 

and the AUDIO OUT port as the modulation source for making AM ACP measurements.

 

 

 

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Agilent Technologies E8285A manual How the Test Set Measures Adjacent Channel Power ACP