Elenco Projects PC1-PC73 - Manual (Page 18)

If continuing from the previous experiment then close the Winscope
program and run it again, to reset the settings. Then use the mouse
to
set it up as shown here, and turn on the switch (snap part S1).
Click on the On-Line button to activate.
You should see a waveform similar to that shown here, but it will be
constantly changing. This is because the siren sound you hear is
not a continuous tone but instead is constantly changing. Note the
differences in the waveshape for this circuit compared to the circuit
in Project PC1.
Your picture may appear different due to variations in the
microphone input designs between computers. See the notes on
page 4 for details.
On-Line
button
Set up
Click on the FFT button to look at the frequency spectrum.
Also set the amplitude and time scales (really amplitude and
frequency scales in FFT mode) to be as shown here.
You should see a fuzzy spectrum similar to that shown here, but it
will be constantly changing. This is because the siren sound you
hear is not a continuous tone but instead is constantly changing
frequency, and it spends more time at some frequencies than at
others.
Note the differences in the spectrum for this circuit
compared to the circuit in Project PC1.
FFT button Amplitude
Time scales
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