Weighting curve

<h2 id="weighting-curves-in-electronic-engineering-audio-and-broadcasting">Weighting curves in electronic engineering, audio, and broadcasting</h2>
<p>Although A-weighting with a slow RMS detector, as commonly used in sound level meters<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> is frequently used when measuring noise in audio circuits, a different weighting curve, <a href="/facts/ITU-R_468_noise_weighting/kMEdMoNM">ITU-R 468 noise weighting</a> uses a psophometric weighting curve and a quasi-peak detector.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> This method, formerly known as <a href="/facts/CCIR_weighting/kMEdMoNM">CCIR weighting</a>, is preferred by the telecommunications industry, broadcasters, and some equipment manufacturers as it reflects more accurately the audibility of pops and short bursts of random noise as opposed to pure tones. <a href="/facts/Psophometric_weighting/RQKyuRC9">Psophometric weighting</a> is used in <a href="/facts/Telephony/2GwTTepw">telephony</a> and <a href="/facts/Telecommunications/vxoj1cxR">telecommunications</a> where narrow-band circuits are common.
Hearing weighting curves are also used for sound in water.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p>
<h2 id="other-applications-of-weighting">Other applications of weighting</h2>
<p>Acoustics is by no means the only subject which finds use for weighting curves however, and they are widely used in deriving measures of effect for sun exposure, gamma radiation exposure, and many other things. In the measurement of <a href="/facts/Gamma_rays/5Drf913J">gamma rays</a> or other <a href="/facts/Ionising_radiation/vw0d9GaT">ionising radiation</a>, a radiation monitor or <a href="/facts/Dosimeter/lc6K3MWK">dosimeter</a> will commonly use a filter to attenuate those energy levels or wavelengths that cause the least damage to the human body, while letting through those that do the most damage, so that any source of radiation may be measured in terms of its true danger rather than just its "strength". The <a href="/facts/Sievert/8HLEH1vG">sievert</a> is a unit of weighted radiation dose for <a href="/facts/Ionising_radiation/vw0d9GaT">ionising radiation</a>, which supersedes the older weighted unit the rem (<a href="/facts/Roentgen_equivalent_man/MkbYB7PN">roentgen equivalent man</a>).
</p><p>Weighting is also applied to the measurement of sunlight when assessing the risk of skin damage through <a href="/facts/Sunburn/Ff6gMYHA">sunburn</a>, since different wavelengths have different biological effects. Common examples are the <a href="/facts/Sun_protection_factor/W6J13MRz">SPF</a> of sunscreen, and the <a href="/facts/Ultraviolet_index/Q5Qg1IeV">ultraviolet index</a>.
</p><p>Another use of weighting is in television, where the red, green, and blue components of the signal are weighted according to their perceived brightness. This ensures compatibility with black-and-white receivers, and also benefits noise performance and allows separation into meaningful <a href="/facts/Luminance_(video)/tepW85uI">luminance</a> and <a href="/facts/Chrominance/Ejtq4s5r">chrominance</a> signals for transmission.
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Weight_function/YNJL7o99">Weight function</a></li>
<li><a href="/facts/Weighted_arithmetic_mean/VHyJfPxb">Weighted arithmetic mean</a></li>
<li><a href="/facts/Weighting/HUltmeDW">Weighting</a></li>
<li><a href="/facts/Weighting_filter/CM88XjPC">Weighting filter</a></li>
<li><a href="/facts/A-weighting/nvBjQ5We">A-weighting</a></li>
<li><a href="/facts/A-weighting/nvBjQ5We">B-, C-, D-, G-, and Z-weightings</a></li>
<li><a href="/facts/M-weighting/kMEdMoNM">M-weighting</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>IEC 61672, which has superseded IEC 60651, IEC 651, and earlier standards <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>IEC 61672, which has superseded IEC 60651, IEC 651, and earlier standards <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>IEC 60268-1 <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Southall, B. L.; Bowles, A. E.; Ellison, W. T.; Finneran, J. J.; Gentry, R. L.; Greene, C. R.; Tyack, P. L.; et al. (2007). "Overview". Aquatic Mammals. 33 (4): 411–414. Bibcode:2007AqMam..33..411S. doi:10.1578/AM.33.4.2007.411. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
</ol>

Weighting curve open-in-new

Weighting curve