72.37.244.124: /* Continuity equation */ small english grammar fix

2014-10-14T20:36:24Z

Continuity equation: small english grammar fix

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	~~[[File:White noise spectrum.svg\|thumb\|Maximum spectral flatness~~ (~~approaching 1) is achieved by white noise.]]~~		Andrew best psychic ([http://myoceancounty.net/groups/apply-these-guidelines-when-gardening-and-grow/ http://myoceancounty.net/groups/apply-these-guidelines-when-gardening-and-grow]) Berryhill is what his wife loves to contact him and he completely digs that title. Alaska is where he's usually been living. One of the issues she loves most is canoeing and she's been performing it for fairly a while. Distributing manufacturing has been his occupation for some time.<br><br>Feel free to visit my website - phone [http://ustanford.com/index.php?do=/profile-38218/info/ love psychic] readings - [http://cpacs.org/index.php?document_srl=90091&mid=board_zTGg26 Highly recommended Internet page],
	~~'''Spectral flatness''' or '''tonality coefficient''',<ref name="johnston88">~~
	~~{{cite journal~~
	~~\|author=J. D. Johnston~~
	~~\|title=Transform coding of audio signals using perceptual noise criteria~~
	~~\|journal=IEEE Journal on Selected Areas in Communications~~
	~~\|volume=6~~
	~~\|issue=2 \|pages=314–332~~
	~~\|year=1988~~
	~~\|doi=10.1109/49.608~~
	~~}}</ref><ref name="Signal Processing Letters">~~
	~~{{cite journal~~
	~~\|author=Shlomo Dubnov~~
	~~\|title=Generalization of Spectral Flatness Measure for Non-Gaussian Linear Processes~~
	~~\|journal=Signal Processing Letters~~
	~~\|volume=11~~
	~~\|issue=8 \|pages=698–701~~
	~~\|year=2004~~
	~~\|issn=1070-9908~~
	~~\|doi=10.1109/LSP.2004.831663~~
	~~}}</ref> also known as '''Wiener entropy''',<ref>~~[http://~~soundanalysispro~~.~~com~~/~~manual-1~~/~~chapter~~-4-~~the~~-~~song~~-~~features~~-of-~~sap2~~/~~wiener-entropy The Song Features › Wiener entropy] "defined as the ratio of geometric mean to arithmetic mean of the spectrum"</ref><ref>[~~http://~~luscinia.sourceforge~~.net/~~page19~~/~~page8/page33/page33.html Luscinia parameters~~] ~~"Wiener entropy~~ is ~~an alternative measure of the noisiness of a signal~~. It is ~~defined as the ratio~~ of the ~~geometric mean to the arithmetic mean of the power spectrum."</ref>~~ is ~~a measure used in [[digital signal processing]] to characterize an audio [[spectrum]]. Spectral flatness is typically measured in [[decibels]],~~ and ~~provides a way to quantify how [[Pitch (music)\|tone]]-like a sound is, as opposed to being [[noise]]-like.<ref name="Signal Processing Letters" />~~

	~~The meaning of~~ '~~'tonal'' in this context is in the sense of the amount of peaks or resonant structure in~~ a ~~[[power spectrum]], as opposed to flat spectrum of a [[white noise]]. A high spectral flatness (approaching 1~~.~~0 for white noise) indicates that the spectrum~~ has a similar amount of power in all spectral bands – this would sound similar to white noise, and the graph of the spectrum would appear relatively flat and smooth. A low spectral flatness (approaching 0.0 for a pure tone) indicates that the spectral power is concentrated in a relatively small number of bands – this would typically sound like a mixture of [[sine wave]]s, and the spectrum would appear "spiky".<~~ref~~>[http://~~recherche~~.~~ircam~~.fr/~~equipes/analyse~~-~~synthese~~/~~peeters~~/~~ARTICLES/Peeters_2003_cuidadoaudiofeatures.pdf A Large Set of Audio Features for Sound Description~~] - ~~technical report published by~~ [~~[IRCAM]] in 2003. Section 9.1</ref>~~

	~~The spectral flatness is calculated by dividing the [[geometric mean]] of the power spectrum by the [[arithmetic mean]] of the power spectrum, i.e.:~~

	:~~<math>~~
	~~\mathrm{Flatness} = \frac{\sqrt[N]{\prod_{n=0}^{N-1}x(n)}}{\frac{\sum_{n=0}^{N-1}x(n)}{N}} = \frac{\exp\left(\frac{1}{N}\sum_{n=0}^{N-1} \ln x(n)\right)}{\frac{1}{N} \sum_{n=0}^{N-1}x(n)}~~
	</~~math>~~

	where ''x(n)'' represents the magnitude of [[histogram\|bin number ''n'']]. Note that a single (or more) empty bin yields a flatness of 0, so this measure is most useful when bins are generally not empty.

	~~The ratio produced by this calculation is often converted to a [[decibel]] scale for reporting, with a maximum of 0 dB and a minimum of −∞ dB.~~

	~~The spectral flatness can also be measured within a specified subband, rather than across the whole band.~~

	~~== Applications ==~~
	~~This measurement is one of the many audio descriptors used in the [[MPEG-7]] standard, in which it is labelled <nowiki>"AudioSpectralFlatness"<~~/~~nowiki>.~~

	In [[bird vocalization\|birdsong]] research, it has been used as one of the features measured on birdsong audio, when testing similarity between two excerpts.<ref>Tchernichovski, O., Nottebohm, F., Ho, C. E., Pesaran, B., Mitra, P. P., 2000. A procedure for an automated measurement of song similarity. ~~Animal Behaviour 59 (6), 1167–1176, {{doi\|10.1006~~/~~anbe.1999.1416}}~~.~~</ref>~~

	== ~~References ==~~

	~~{{Reflist}}~~

	~~[[Category:Digital signal processing]~~]

en>Chris Howard: /* Further reading */ added foreword author name

2014-01-31T23:15:02Z

Further reading: added foreword author name

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en>Phil Boswell: /* Quantum potential and relativity */convert dodgy URL to ID using AWB

2012-08-29T18:55:10Z

Quantum potential and relativity: convert dodgy URL to ID using AWB

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Quantum potential - Revision history

72.37.244.124: /* Continuity equation */ small english grammar fix

en>Chris Howard: /* Further reading */ added foreword author name

en>Phil Boswell: /* Quantum potential and relativity */convert dodgy URL to ID using AWB