Adobe AUDITION 1.5 - Manual (Page 276)

268
Digital Audio Primer
Waveforms
Amplitude reflects the change in pressure from the peak of the waveform to the trough.
Cycle describes the amount of time it takes a waveform to return to the same amplitude
level. Frequency describes the number of cycles per second, where one Hertz (Hz) equals
one cycle per second. That is, a waveform at 1000 Hz goes through 1000 cycles every
second. Phase measures how far through a cycle a waveform is. There are 360 degrees in a
single cycle; if you start measuring at the zero line, a cycle reaches 90 degrees at the peak,
180 degrees when it crosses the zero line, 270 degrees at the trough, and 360 degrees when
it completes at zero. Wavelength is the distance, measured in units such as inches or centi-
meters, between two points with the same degree of phase.
A single cycle at left; a 20 Hz waveform at right
A. Wavelength B. Degree of phase C. Amplitude D. One second
When two or more sound waves meet, their amplitudes add to and subtract from each
other. If the peaks and troughs of the two waveforms line up, they are said to be in phase.
In this case, each peak adds to the peak in the other waveform, and each trough subtracts
from the other trough, resulting in a waveform that has higher amplitude than either
individual waveform.
C
A
B
A
D
0º
90º
270º
180º 360º
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