Noise weighting


Noise weighting

A noise weighting is a specific amplitude-vs.-frequency characteristic that is designed to allow subjectively valid measurement of noise. It emphasises the parts of the spectrum that are most important.

Usually, noise means audible noise, in audio systems, broadcast systems or telephone circuits. In this case the weighting is sometimes referred to as Psophometric weighting, though this term is best avoided because, although strictly a general term, the word Psophometric is sometimes assumed to refer to a particular weighting used in telecommunications.

A major use of noise weighting is in the measurement of residual noise in audio equipment, usually present as hiss or hum in quiet moments of programme material. The purpose of weighting here is to emphasise the parts of the audible spectrum that our ears perceive most readily, and attenuate the parts that contribute less to our perception of loudness, in order to get a measured figure that correlates well with subjective effect.

The ITU-R 468 noise weighting was devised specifically for this purpose, and is widely used in broadcasting, especially in the UK and Europe. A-weighting is also used, especially in the USA, though this is only really valid for the measurement of tones, not noise, and is widely incorporated into sound level meters.

In telecommunication, noise weightings are used by agencies concerned with public telephone service, and various standard curves are based on the characteristics of specific commercial telephone instruments, representing successive stages of technological development. The coding of commercial apparatus appears in the nomenclature of certain weightings. The same weighting nomenclature and units are used in military versions of commercial noise measuring sets.

Telocommunication measurements are made in lines terminated either by the measuring set or the an instrument of the relevant class.

See also


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • ITU-R 468 noise weighting — The ITU R 468 weighting curve (originally defined in CCIR recommendation 468) is widely used when measuring noise in audio systems, especially in the UK, Europe, and former countries of the British Empire such as Australia and South Africa. It is …   Wikipedia

  • Noise measurement — is carried out in various fields. In acoustics, it can be for the purpose of measuring environmental noise, or part of a test procedure using white noise, or some other specialised form of test signal. In electronics it relates to the sensitivity …   Wikipedia

  • Noise health effects — are the health consequences of elevated sound levels. Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. Changes in the immune… …   Wikipedia

  • Weighting filter — A weighting filter is used to emphasise or suppress some aspects of a phenomenon compared to others, for measurement or other purposes. Contents 1 Audio application …   Wikipedia

  • Weighting — The process of weighting involves emphasising some aspects of a phenomenon, or of a set of data giving them more weight in the final effect or result. It is analogous to the practice of adding extra weight to one side of a pair of scales to… …   Wikipedia

  • Noise (audio) — Noise in audio, recording, and broadcast systems refers to the residual low level sound (usually hiss and hum) that is heard in quiet periods of a programme. In audio engineering, it can refer either to the acoustic noise from loudspeakers, or to …   Wikipedia

  • Noise regulation — includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. After the watershed passage of the United States Noise Control Act of 1972,[1] other local and state… …   Wikipedia

  • Noise, vibration, and harshness — (NVH), also known as noise and vibration (N V), is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks. While noise and vibration can be readily measured, Harshness is a subjective… …   Wikipedia

  • Noise, Vibration, and Harshness — Noise, Vibration, and Harshness, also known as Noise and Vibration, abbreviated to NVH and N V respectively, is the name given to the field of measuring, and modifying, the noise and vibration characteristics of vehicles, particularly cars and… …   Wikipedia

  • Weighting curve — A Weighting curve is a graph of a set of factors, that are used to weight measured values of a variable according to their importance in relation to some outcome. The most commonly known example is frequency weighting in sound level measurement… …   Wikipedia


We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.