Several measurements describe waveforms:

Amplitude

Reflects the change in pressure from the peak of the waveform to the trough. High-amplitude waveforms are loud; low-amplitude waveforms are quiet.

Cycle

Describes a single, repeated sequence of pressure changes, from zero pressure, to high pressure, to low pressure, and back to zero.

Frequency

Measured in hertz (Hz), describes the number of cycles per second. (For example, a 1000-Hz waveform has 1000 cycles per second.) The higher the frequency, the higher the musical pitch.

Phase

Measured in 360 degrees, indicates the position of a waveform in a cycle. Zero degrees is the start point, followed by 90º at high pressure, 180º at the halfway point, 270º at low pressure, and 360º at the end point.

Wavelength

Measured in units such as inches or centimeters, is the distance between two points with the same degree of phase. As frequency increases, wavelength decreases.

A single cycle at left; a complete, 20-Hz waveform at right

A.

Wavelength

B.

Degree of phase

C.

Amplitude

D.

One second