Computer Music: Musc 216
Digial Noise: Aliasing

ALIASING is a type of digital noise that results when a sample rate is too low to acurately represent the waveform. Standard practice is to use a sample rate that is greater than TWICE the frequency of the wave. For example, consider the following SINE wave at 8 Hz (8 cycles in ONE second) sampled at 44,100 samples:

Sampled at 34 Hz (34 samples instead of 44,100):

This would result in an actual wave which looks like a TRIANGLE:

Sampled at 12Hz would resulet in this:

Which would result in an actual wave which looks like this:

Notice how the FREQUENCY of the wave is now only 3 Hz.