138 Chapter 2 
Front-Panel Key Reference
Meas Setup
Harmonic Distortion Meas Setup Menu Keys
To access the following keys for setting up a harmonic distortion 
measurement, press 
MEASURE, Harmonic Distortion and then the 
front-panel 
Meas Setup key. 
Avg Number 
On Off
Press Avg Number (On) to specify the number of averages used when 
calculating the measurement result. The average will be displayed at 
the end of each sweep. (Off) disables measurement averaging.
Key Access: 
Meas Setup
Avg Mode 
Exp Repeat
Allows you to select the type of termination control used for the 
averaging function. This determines the averaging action after the 
specified number of measurements (average count) is reached. 
Avg Mode has no effect on measurements that are not averaged.
Exp  Each successive data acquisition after the average 
count is reached is exponentially weighted and 
combined with the existing average. Exponential 
averaging weights new data more than old data, which 
facilitates tracking of slow-changing signals.
Repeat  After reaching the average count, all previous result 
data is cleared and the average count is set back to 1. 
Key Access: 
Meas Setup
Harmonics Harmonics
 indicates the number of harmonics to measure before 
computing the total harmonic distortion. The minimum number is 2 
(only the fundamental and second harmonic will be measured). The 
maximum number is 10.
Key Access: 
Meas Setup
ST/Harmonic
Auto Man
ST/Harmonic
 (Auto) sets the sweeptime to 200 divided by the resolution 
bandwidth or 10 ms, whichever is greater. 
ST/Harmonic (Man) allows 
you to specify any sweeptime from 10 ms to the analyzer maximum. 
This sweeptime is used only for measuring harmonics. The sweeptime 
set before the measurement began is used for finding the fundamental.
Key Access: 
Meas Setup
Optimize
Ref Level
Sets the reference level and attenuator to optimum values based on the 
signal present at the input. 
Key Access: 
Meas Setup