Elenco PK101 w/ Computer Interface - Manual (Page 10)

Now its time to look at your electronic signal in a different way. The oscilloscope features you have
been using show you voltage (amplitude) vs time, now you will see voltage vs frequency. Engineers
use expensive instruments called spectrum analyzers to do this, but Winscope uses a mathematical
transformation called an FFT to do this. Set the Y1 gain control back to its default position for now.
Click on the 5ms/div button to display a wider range, then click on the FFT button. Your display
should be similar to this:
You are seeing the frequency
spectrum of your signal, up to 22
KHz. Notice that most of the ener-
gy is at the low frequencies
(below 7 KHz), and there is very
little as you go higher.
The 1:1 gain mode does not apply to the FFT screen, so move the Y1 gain control down to here so
you can see the peak energy at the low frequencies.
Move the variable resistor control
and watch how it changes the fre-
quencies on the display.
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