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APPARATUS

Lissajous figures show when the frequency ratio is that of two small integers.  Let f₂ be the higher frequency.  When f₂ = 3/2 f₁ you can also hear the difference tone 1/2 f₁ if the two tones are loud enough.  Upon slight mistuning you hear beats in the low tone, possibly between the intercombination tones  f₂- f₁ and 2 f₁- f₂.  Also when  f₂ = 5/4  f₁ you often can hear a tone of frequency 3/4 f₁ .  When f₂ = f₁ , upon slight mistuning you hear more dissonance from square waves than from sine waves (Helmholtz theory of consonance).

-REW

NOTES

At least one of the function generators should have good fine tuning control.

Each oscillator output should go to one channel of a stereo amplifier and to the vertical or horizontal input of the scope in x-y mode.  The output of the amplifiers is then sent to two speakers.

AJP 49(7),632