Purpose: Provide a Lissajous type display from a single vocal source.
Description: The signal from a microphone is amplified and fed into a circuit which produces two signals which are different in phase, and these two signals are fed into the X and Y coordinates of the oscilloscope to create a type of Lissajous pattern. The circuit makes the two signals exactly 90 degrees apart at 300 Hz, producing a circle. For other frequencies the phase shift is different and various figures are formed.
