DSP Basics

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Pendulum Motion

Simple harmonic motion produces sine waves, like in this here pendulum:

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Two Domains of Description

There are two different ways to represent sound waveforms: time-domain, and frequency-domain. In the time-domain, the graph represents air pressure vs. time, with air pressure on the vertical axis. When the "curve is near the bottom of the graph, the air pressure is lower, and when the curve is near the top of the graph, the air pressure has increased". The frequency-domain (also known as spectrum) representation shows the frequency content of a sound. The individual frequency components are referred to as harmonics or partials, depending on their relationship to the fundamental frequency.

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Plotting a Sine Wave in the Time Domain

Function to plot a sine wave: d=A sin(2πft+0)

d=displacement A=amplitude f=frequency t=time phase = 0

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Mixing Audio Signals

mix = (buffer1 + buffer2 + buffer3 ...) / number of buffers

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