ENDEVCO
www.endevco.com Tel: +1 (866) ENDEVCO [+1 (866) 363-3826]
IM 2680/5 083119
13
4.8
What to look for?
Exercise caution and do not operate too close to the full - scale output.
Clipping can occur (Figure 6D) once the signal reaches 0 volts or the
maximum voltage and in the region just prior to clipping, the amplitude is
non-linear (see figure 5).
An oscilloscope with an FFT function is an excellent tool for checking
signals close to the full-scale output. When using the FFT mode, a
Hanning window is recommended.
Using the FFT mode on the oscilloscope, view the frequency domain and
observe the presence of harmonics. The below image shows the spectrum
of an undistorted sine wave. Only a single frequency is present.
In some cases the time domain display on the oscilloscope can appear as
clean as figure 6A, but there may be distortion present that will only be
detectable in the frequency domain or on a harmonic distortion analyzer.
A clean sine wave in
the time domain
(Figure 6A)
(Figure 6B)
Amplitude
Amplitude
Frequency
