Ceyear 4041 Series, User Manual

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Chapter IV Spectrum Analyzer Mode
46
Fig 4-19 Second harmonic wave amplitude
I) Calculate the harmonic distortion.
Convert the distortion percentage between the second harmonic wave and fundamental wave as per Fig 4-17. The
unit can be converted to Volt for the convenience of reading the voltage ratio of two signals.
j) Measure other harmonic waves.
Repeat the steps (i) to (j) for other harmonic waves which you want to measure. Calculate the distortion
percentage, %, of each harmonic wave.
The total harmonic distortion percentage of the signal is also a parameter to be tested in general condition. In
order to test this parameter, the amplitude of each harmonic wave must be tested in the linear unit (e.g., Volt), but
not the relative unit, dBc. Press
【
Ampt
】
, [Amplitude Unit], [Volt]. This amplitude unit will be Volt. The signal
amplitude obtained from the measurement can be employed in the equation below for calculation of the total
harmonic distortion:
     
%
100
distortion harmonic Total
1
2 2
3
2
2
A
A A A
n
     

Where,
A
1
——
Amplitude of fundamental wave, in Volt
A
2
——
Amplitude of second harmonic wave, in Volt
A
3
——
Amplitude of third harmonic wave, in Volt
A
n
——
Amplitude of n harmonic wave, in Volt
If the signal amplitude can be measured carefully according to the foregoing examples, the harmonic distortion
percentage obtained from this process will be very accurate.