From an acoustic point of view, all irregular or random acoustic signals are called noise.From a psychological point of view, all unwanted noises are called noise .Even beautiful music is noise if it interferes with people’s sleep or thinking.The noise described below is mainly considered from the perspective of acoustics.
1. White noise
White noise is a very useful type of noise in auditory research.Just as optics contains all kinds of light that are white light, the name of white noise has already explained its nature. It refers to the sound energy carried by the frequency bands of various bandwidths in a wide frequency range. Equal noise.
2. Bandpass noise
White noise with continuous spectrum and constant power spectral density.After being filtered by a bandpass filter, it becomes bandpass noise, which can be divided into broadband noise and narrowband noise.
3. Impulse noise
Impulse noise refers to noise of short duration.The sounds of guns and other weapons, such as fires, explosions, and industrial hammers and punches are all impulse sounds.Sometimes a pulse signal with a peak pressure exceeding 177dBSL and a longer duration is called a shock wave or pressure wave.
4. Speech noise