What is White Noise?

White noise refers to noise whose power spectral density is constant throughout the frequency domain. Random noise with the same energy density at all frequencies is called white noise. From the frequency response of our ears it sounds like a very bright "snoring" sound (every octave higher, the frequency doubles. Therefore the energy in the high frequency region is also significantly enhanced).

White Noise

White noise refers to the

It is a newly-created infinite-dimensional Schwartz extensive function theory,

Constant power spectral density: S () = S0

Signal autocorrelation: R () = S0 ()

Mathematical expectations: E (X (t)] = 0

Mean square value: E [X (t) ^ 2] <

Where () is the Dirac function.

White noise is a general term for random fluctuation noise. Its amplitude follows a Gaussian (normal) distribution, while the power spectrum is similar to the white spectrum and is evenly distributed over the entire frequency axis, so it is called white noise. White noise mainly includes three types: thermal noise caused by electronic Brownian motion in conductors such as resistors and feeders; shot noise due to non-uniformity of electron emission in active devices such as vacuum tubes and semiconductor devices ; And the cosmic noise generated by the celestial body radiation waves to the receiver. The first two categories are the main ones.

Some types of noise in communication can be eliminated, some can be avoided, and some can be reduced. White noise, which is mainly internal noise, is always ubiquitous and unavoidable in both the time and frequency domains. Therefore, it has become a key research object for various types of noise in communication.

One of the application areas of white noise is architectural acoustics. In order to reduce distracting and undesired noise (such as human conversation) in the internal space, continuous low-intensity noise is used as the background sound. Some sirens of emergency vehicles also use white noise because white noise can pass through, for example, cities

White noise is not "noise"

It is the power spectrum of a random signal in the same unit. This is a good signal frequency. It is a theoretical construction. Just like the full-color white color light spectrum, white noise fills the vibration frequency that can be heard by the entire human ear, which can help a person relax or sleep. Life is full of sound and noise interference, such as car honking, barking dogs, noisy snoring, sirens, yelling. White noise does not increase drum noise, white noise, but includes all calls of the same frequency. Studies show that A stable, peaceful sound is as monotonous as white noise, which can filter and disperse noise to help reduce noise distractions, which is why it is used to help people relax and sleep.