atom03:Noise
From student
Noise can be divided into 4 different categories:
- Continuous > noise which remains constant and stable over a given time period
- Variable > Different operations or different noise sources cause the sound changes over time
- Intermittent > Mix of relatively quiet and noisy periods
- Impulsive > A very short instant of loud noise
Source: http://www.ccohs.ca/oshanswers/phys_agents/noise_basic.html#_1_10 (visited 23-09-2011)