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| | I am Terrance from Uscio. I love to play Euphonium. Other hobbies are Programming.<br><br>my web site :: [http://mediagoblin.tami.org.il/u/urzzm/ белково углеводная диета] |
| In [[electronics]], an '''octave''' is a doubling or halving of a [[frequency]]. The term is derived from the Western musical scale (an [[octave]] is a doubling in frequency) and is therefore common in audio electronics. (The prefix [[octa-]], denoting eight, has no direct significance.) Along with the [[decade (log scale)|decade]], it is a [[units of measurement|unit]] used to describe [[frequency|frequency bands]] or [[interval ratio|frequency ratios]].<ref>Levine, William S. (2010). ''The Control Handbook: Control System Fundamentals'', p.9-29. ISBN 9781420073621/ISBN 9781420073669.</ref><ref>Perdikaris, G. (1991). ''Computer Controlled Systems: Theory and Applications'', p.117. ISBN 9780792314226.</ref>
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| A frequency ratio expressed in octaves is the base-2 [[logarithm]] ([[binary logarithm]]) of the ratio:
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| : <math>\mathrm{octaves} = \log_2\left(\frac{f_2}{f_1}\right)</math> | |
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| An amplifier or filter may be stated to have a frequency response of ±6dB per octave over a particular frequency range, which signifies that the power gain changes by ±6 [[decibels]] (a factor of 4 in power), when the frequency changes by a factor of 2. This slope, or more precisely <math>10\log_{10}(4) \approx 6.0206</math> decibels per octave, corresponds to an amplitude gain proportional to frequency, which is equivalent to ±20dB per [[decade (log scale)|decade]] (factor of 10 amplitude gain change for a factor of 10 frequency change). This would be a [[first-order filter]].
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| ==Example==
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| 1. The distance between the frequencies 20 Hz and 40 Hz is 1 octave.
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| 2. An amplitude of 52 dB at 4 kHz decreases as frequency increases at −2 dB/octave. What is the amplitude at 13 kHz?
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| : <math>\text{number of octaves} = \log_2\left(\frac{13}{4}\right) = 1.7</math>
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| : <math>\text{Mag}_{13\text{ kHz}} = 52\text{ dB} + (1.7\text{ octaves} \times -2\text{ dB/octave}) = 48.6\text{ dB}.\,</math>
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| ==References==
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| {{reflist}}
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| [[Category:Acoustics]]
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| [[Category:Audio electronics]]
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| {{electronics-stub}}
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Latest revision as of 06:19, 11 January 2015
I am Terrance from Uscio. I love to play Euphonium. Other hobbies are Programming.
my web site :: белково углеводная диета