Thd Ratio And Thd Level Measurements - Keysight U8903B User Manual

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 ratio
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
Keysight U8903B User's Guide
rms value of distortion
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
= 20 Log 10
⎝
rms value of signal and distortion
Analog Analyzer > Functions > THD Ratio menu page 1
Audio Analyzer Measurement Functions
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⎠
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