Electronic noise
From Wikipedia, the free encyclopedia
Electronic noise is an unwanted signal characteristic of all electronic circuits. Depending on the circuit, the noise put out by electronic devices can vary greatly. This noise comes from many different electronic effects.
Thermal noise and shot noise are inherent to all devices. The other types depend mostly on manufacturing quality and semiconductor defects.
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[edit] Types
[edit] Shot noise
Shot noise in electronic devices consists of random fluctuations of the electric current in an electrical conductor, which are caused by the fact that the current is carried by discrete charges (electrons).
[edit] Thermal noise
Johnson-Nyquist noise (sometimes thermal noise, Johnson noise or Nyquist noise) is the noise generated by the equilibrium fluctuations of the electric current inside an electrical conductor, which happens regardless of any applied voltage, due to the random thermal motion of the charge carriers (the electrons).
[edit] Flicker noise
Flicker noise, also known as 1/f noise, is a signal or process with a frequency spectrum such that the power spectral density is proportional to the reciprocal of the frequency. In other words, it is a sound that falls off steadily into the higher frequencies, with a pink spectrum, instead of producing all frequencies equally.
[edit] Burst noise
Burst noise consists of sudden step-like transitions between two or more levels (non-Gaussian), as high as several hundred millivolts, at random and unpredictable times. Each shift in offset voltage or current lasts for several milliseconds, and the intervals between pulses tend to be in the audio range (less than 100 Hz), leading to the term popcorn noise for the popping or crackling sounds it produces in audio circuits.
[edit] Avalanche noise
See Avalanche diode and Avalanche breakdown.
