PURPOSE: To show how frequencies can be matched using Lissajous figures.
DESCRIPTION: Obtain a Lissajous figure using a sine wave oscillator (on the horizontal axis) and a musical sound such as a voice or instrument (on the vertical axis). In the photograph above, a soft male falsetto voice (approximately a sine wave) was used on the vertical axis to produce the Lissajous figure, then grabbed by the scope for a stable display. The frequency of the oscillator is displayed at the upper right of the oscilloscope tube. Using the Lissajous figure and the frequency of the oscillator the frequency of the musical note can be determined.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: Microphone with mic amplifier, oscillator, and oscillscope.
SETUP TIME: 5 min.
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