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Распределяйте работы автоматически и собирайте отзывы анонимно. Please enable it for a better experience of Jumi. This history is reasonably comprehensive, but not yet complete. I worked on it in 2009 and made some updates in June and July 2013 and June 2014. In February 2016 I adding an English translation of the 1933 Ulrich Steudel paper which pioneered this field.

While I have collated this information, and at times added my own commentary, the most significant part of what lies below is that we now have good English translations of some German papers from the 1930s to the 1950s. The people who have worked on these translations have not all been directly involved in this particular audio field. Thanks very much to the translators whose work has been crucial to the development of this page! If you have anything to add or this – any documents, corrections, comments, suggestions etc. The scope of this history This history focuses on a particular type of audio noise measurement. This page does not concern high-level noise, such as the health-threatening environmental noise in workplaces, or in residential areas due to nearby road traffic or aircraft.

This field primarily concerns assigning a single number to the measured noise signal in isolation, rather than multiple numbers or a spectrum of what the human auditory tract would perceive. The most significant technical standards in this field are CCIR 468 and its derivatives, involving quasi-peak detection of the filtered noise signal. However, these techniques are only used by some equipment manufacturers at present. Many or most manufacturers give dBA figures for background noise. CCIR 468 approach and other approaches. The continuous background noise of pre-amplifiers and analogue-to-digital converters. Interference from external sources such as radio transmitters in cell-phones.

Power-supply noise in computers or perhaps ground-noise between systems, such as between a personal computer and an external audio amplifier or pre-amp. This noise may vary with CPU activity. These sources of unwanted signal are not caused by or related to the audio programme. If they were, then this would be a form of intermodulation “distortion”, including perhaps how the input signal alters the behaviour of a poorly designed sigma-delta analogue to digital converter to produce “birdie” tones. Since human audio perception is strongly affected by level, when measuring a noise signal in analogue electronic form or in a digital datastream or file, it is necessary to relate this to a physical noise level presented to the listener’s ears.