Keysight U8903B - THD Ratio and THD Level Measurements

Audio Analyzer Measurement Functions 4
Keysight U8903B User’s Guide 203
THD ratio and THD level measurements
THD (Total Harmonic Distortion) measures the selected harmonics amplitude that are
generated due to the nonlinearity of the DUT and adding up the harmonics amplitude. The
THD measurement will exclude any noise components that may be present in the DUT.
THD Ratio is defined as the ratio of the THD Level relative to the fundamental signal
amplitude, and it is expressed in dB (default) or as a percentage. The THD Ratio can be
computed as follows.
THD+N Ratio measurement function mode is applicable for the analog, digital, and
Bluetooth analyzer. The settings for THD ratio measurement are displayed as shown in
Figure 4-27, Figure 4-28, and Figure 4-29 for the analog, digital, and Bluetooth analyzer
respectively.
Figure 4-27 Analog Analyzer > Functions > THD Ratio menu page 1
THD ratio 20 Log
10
rms value of distortion
rms value of signal and distortion
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