Avalanche noise: This is a form of noise that is generated when a junction diode is operated close to the point of avalanche breakdown. This occurs in semiconductor junctions when the carriers in a high voltage gradient develop sufficient energy to dislodge additional carriers through physical impact. The current generated by this is not even as it is determined by high energy electrons hitting the crystal lattice to generate more hole electron pairs. As a result it is a very noisy process.
Flicker noise, 1/f noise: This type of noise occurs in almost all electronic devices. It has a variety of causes, each related to the direct current flow. It has a frequency spectrum that falls off steadily into the higher frequencies.
Phase noise: Phase noise is a form of RF noise that is visible on radio frequency, and other signals. It appears in the form of phase jitter or perturbations on the signal. These manifest themselves as sidebands that spread out either side of the signal or carrier. Phase noise can affect a signal or system in a variety of ways. One major area is when phase modulation is used to carry digital information. Phase noise can degrade the bit error rate, as the noise can disrupt the phase changes that indicate the state of the data to be transmitted.
Shot noise: This form of noise that arises from the time-dependent fluctuations in electrical current. This is caused by the discrete nature of electron charges. Shot noise is particularly noticeable in semiconductor devices, such as tunnel junctions, Schottky barrier diodes and p-n junctions.
Thermal noise: This form of noise, also referred to as Johnson or Johnson Nyquist noise arises as a result of the thermal agitation of charge carriers - typically electrons - in a conductor. As the temperature, and hence the agitation of the charge carriers increases so does the level of noise.
This noise is a major form of noise experienced in low noise amplifiers and the like. To reduce it, very high performance amplifiers, e.g. those used for radio astronomy, etc., have been operated at very low temperatures. Figures like noise temperature are used as a measure of the level of this thermal noise.
Burst noise: Is a form of noise found in some circuits where the operation of the semiconductor gives rise to a sudden impulse. As a result of the sound heard on audio circuits, it is often referred to as popcorn noise.