Selvstøj

Selvstøj, a Danish term, translates to "self-noise" in English and refers to the inherent random fluctuations within an electronic system or device that are present even when there is no external input signal. This noise is generated by the fundamental physical processes within the components themselves.

Sources of selvstøj include thermal noise, also known as Johnson-Nyquist noise, which arises from the random thermal motion of charge carriers in conductive materials. Another significant contributor is shot noise, which is caused by the discrete nature of electric charge and the random arrival of charge carriers across a potential barrier, such as in a semiconductor junction. Flicker noise, or 1/f noise, is another type of self-noise that is more prevalent at lower frequencies and is often associated with imperfections in materials and interfaces.

Selvstøj is a critical parameter in the performance of many electronic devices, particularly those that amplify weak signals, such as audio amplifiers, sensitive measurement instruments, and radio receivers. A device with low selvstøj is desirable because it can detect and process signals that are close to or below the noise floor, leading to a higher signal-to-noise ratio. Conversely, high selvstøj can mask weak signals, making them indistinguishable from the noise, thus limiting the sensitivity and accuracy of the system. Minimizing selvstøj is a key design consideration in the development of high-performance electronic equipment.