Power ratio compared to decibel - Revision history

wikademia>Eme: moved Power ratio vs decibel to Power ratio compared to decibel

2010-11-30T05:36:15Z

moved Power ratio vs decibel to Power ratio compared to decibel

← Older revision	Revision as of 05:36, 30 November 2010
(No difference)

wikademia>Eme at 22:22, 23 December 2009

2009-12-23T22:22:17Z

← Older revision		Revision as of 22:22, 23 December 2009
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	~~{{AfDM\|page=Power ratio vs decibel\|logdate=2009 September 24\|substed=yes\|help=off}}~~
	~~<!-- For administrator use only: {{oldafdfull\|page=Power ratio vs decibel\|date=24 September 2009\|result='''keep'''}} -->~~
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	~~[[File:DB table.jpg\|right]]~~

	'''[[Decibel]]''' is a practical unit which expresses a ratio in [[logarithmic]] scale. It is used in many engineering applications. For example the ratio of output power with respect to input power can be given in decibels (''abbreviation'' '''dB'''). As the name of the unit imply, decibel is actually a submultiple of the unit '''bel'''. (after the British inventor [[Alexander Graham Bell]] (1847-1922)) But in practice, bell is seldom used.		'''[[Decibel]]''' is a practical unit which expresses a ratio in [[logarithmic]] scale. It is used in many engineering applications. For example the ratio of output power with respect to input power can be given in decibels (''abbreviation'' '''dB'''). As the name of the unit imply, decibel is actually a submultiple of the unit '''bel'''. (after the British inventor [[Alexander Graham Bell]] (1847-1922)) But in practice, bell is seldom used.

wikademia>Wikademia: 11 revisions

2009-09-27T00:19:33Z

11 revisions

← Older revision	Revision as of 00:19, 27 September 2009
(No difference)

wikademia>Favonian: Nominated for deletion; see Wikipedia:Articles for deletion/Power ratio vs decibel. (TW)

2009-09-24T06:09:58Z

Nominated for deletion; see Wikipedia:Articles for deletion/Power ratio vs decibel. (TW)

← Older revision		Revision as of 06:09, 24 September 2009
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			{{AfDM\|page=Power ratio vs decibel\|logdate=2009 September 24\|substed=yes\|help=off}}
			<!-- For administrator use only: {{oldafdfull\|page=Power ratio vs decibel\|date=24 September 2009\|result='''keep'''}} -->
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	[[File:DB table.jpg\|right]]		[[File:DB table.jpg\|right]]

212.175.166.246 at 05:41, 24 September 2009

2009-09-24T05:41:29Z

← Older revision		Revision as of 05:41, 24 September 2009
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	{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}
	~~<!-- Do not use the "dated prod" template directly; the above line is generated by "subst:prod\|reason" -->~~
	[[File:DB table.jpg\|right]]		[[File:DB table.jpg\|right]]

	'''[[Decibel]]''' is a practical unit which expresses a ratio in [[logarithmic]] scale. It is used in many engineering applications. For example the ratio of output power with respect to input power can be given in decibels (''abbreviation'' '''dB'''). As the name of the unit imply, decibel is actually a submultiple of the unit '''bel'''. But in practice bell is seldom used.		'''[[Decibel]]''' is a practical unit which expresses a ratio in [[logarithmic]] scale. It is used in many engineering applications. For example the ratio of output power with respect to input power can be given in decibels (''abbreviation'' '''dB'''). As the name of the unit imply, decibel is actually a submultiple of the unit '''bel'''. (after the British inventor [[Alexander Graham Bell]] (1847-1922)) But in practice, bell is seldom used.


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	* '''37 dB''' = 10 dB + 10 dB + 10 dB - 3 dB		* '''37 dB''' = 10 dB + 10 dB + 10 dB - 3 dB

	The ratio = 10• 10• 10• 10 / 2 ≈ '''~~5000~~'''		The ratio = 10• 10• 10• 10 / 2 ≈ '''5 000'''


			* '''44 dB''' = 10 db + 10 dB + 10 dB + 10 dB + 10 dB - 3 dB -3 dB

			The ratio = 10<sup>5</sup>/ 2<sup>2</sup> ≈ '''25 000'''

wikademia>R'n'B: remove {{hangon}}, doesn't apply

2009-09-23T15:22:46Z

remove {{hangon}}, doesn't apply

← Older revision		Revision as of 15:22, 23 September 2009
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	{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}		{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}
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	~~{{hangon}}~~
	[[File:DB table.jpg\|right]]		[[File:DB table.jpg\|right]]

wikademia>Nedim Ardoğa at 12:47, 23 September 2009

2009-09-23T12:47:50Z

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	{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}		{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}
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			{{hangon}}
	[[File:DB table.jpg\|right]]		[[File:DB table.jpg\|right]]

wikademia>Nedim Ardoğa at 08:41, 22 September 2009

2009-09-22T08:41:02Z

← Older revision		Revision as of 08:41, 22 September 2009
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	== ~~Ratio~~ expressed in dB ==		== Gain expressed in dB ==


	The definition of power ~~ratio~~ in dB is as follows		The definition of power gain in '''dB''' is as follows

	<div style="border:2px solid #000000; border-collapse:collapse; width:30%; padding:1em;">		<div style="border:2px solid #000000; border-collapse:collapse; width:30%; padding:1em;">
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	</div>		</div>

	In this equation, '''G''' is the gain in '''dB''', '''P<sub>o</sub>''' is the output power and '''P<sub>i</sub>''' is the input power. It can be seen that the ~~ratio~~ in '''dB''' is positive for power ~~gain~~, and negative for power loss. So the gain of an amplifier is expressed by positive decibels and the attenuation of an attenuator or a power splitter is expressed by negative decibels.		In this equation, '''G''' is the gain in '''dB''', '''P<sub>o</sub>''' is the output power and '''P<sub>i</sub>''' is the input power. It can be seen that the gain in '''dB''' is positive for power increase, and negative for power loss. So the gain of an amplifier is expressed by positive decibels and the attenuation of an attenuator or a power splitter is expressed by negative decibels.

	== The table ==		== The table ==


	The accompanying table gives the decibels for power ~~gain~~. The first column is the power ~~gain~~ in terms of the quotient '''(P<sub>0</sub>/P<sub>i</sub>)''' and the second column is the '''decibel''' equivalent. (The same table can be used for the power loss also. But in this case, the the reciprocal of the power loss must be used and the correspanding '''dB''' figure must have a minus sign.)		The accompanying table gives the decibels for power ratio. The first column is the power ratio in terms of the quotient '''(P<sub>0</sub>/P<sub>i</sub>)''' and the second column is the '''decibel''' equivalent. (The same table can be used for the power loss also. But in this case, the the reciprocal of the power loss must be used and the correspanding '''dB''' figure must have a minus sign.)


	== From decibel to ratio ==		== From decibel to ratio ==

			In order to convert gain (in '''dB''') to power ratio, the [[colog]] of '''G/10''' can be used;

	~~If a ratio is known in decibels~~ it is ~~usually~~ possible to convert it to power ~~gain~~ without using a logarithmic table. Since, all integer numbers in dB can be expressed in terms of either addition or subtraction of threes and tens, only the following should be known;		: <math> \frac{P_o}{P_i}= 10^{\frac{G}{10}}</math>

			But for integer values it is possible to convert the gain to power ratio without using a logarithmic table. Since, all integer numbers in '''dB''' can be expressed in terms of either addition or subtraction of threes and tens, only the following should be known;

	* '''10 dB''' correspands to '''x 10'''		* '''10 dB''' correspands to '''x 10'''

wikademia>Nedim Ardoğa at 05:36, 20 September 2009

2009-09-20T05:36:49Z

← Older revision		Revision as of 05:36, 20 September 2009
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	If a ratio is known in decibels it is usually possible to convert it to power gain without using a logarithmic table. Since, all integer numbers in dB can be expressed in terms of either addition or subtraction of threes and tens, only the following should be known;		If a ratio is known in decibels it is usually possible to convert it to power gain without using a logarithmic table. Since, all integer numbers in dB can be expressed in terms of either addition or subtraction of threes and tens, only the following should be known;

	* 10 dB correspands to x 10		* '''10 dB''' correspands to '''x 10'''
	* 3 dB correspands to x 2		* '''3 dB''' correspands to '''x 2'''
	* -sign correspands to division		* '''-'''sign correspands to division

wikademia>Nedim Ardoğa at 05:52, 19 September 2009

2009-09-19T05:52:16Z

← Older revision		Revision as of 05:52, 19 September 2009
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	The definition of power ratio in dB is as follows		The definition of power ratio in dB is as follows

	<div style="border:2px solid #000000; border-collapse:collapse; width:35%; padding:1em;">		<div style="border:2px solid #000000; border-collapse:collapse; width:30%; padding:1em;">

	: <math> \mbox{~~Ratio in dB~~} = 10\cdot \log{\frac{P_o}{P_i}}</math>		: <math> \mbox{G} = 10\cdot \log{\frac{P_o}{P_i}}</math>

	</div>		</div>

	In this equation '''P<sub>o</sub>''' is the output power and '''P<sub>i</sub>''' is the input power. It can be seen that the ratio in '''dB''' is positive for power gain, and negative for power loss. So the gain of an amplifier is expressed by positive decibels and the attenuation of an attenuator or a power splitter is expressed by negative decibels.		In this equation, '''G''' is the gain in '''dB''', '''P<sub>o</sub>''' is the output power and '''P<sub>i</sub>''' is the input power. It can be seen that the ratio in '''dB''' is positive for power gain, and negative for power loss. So the gain of an amplifier is expressed by positive decibels and the attenuation of an attenuator or a power splitter is expressed by negative decibels.

	== The table ==		== The table ==

← Older revision		Revision as of 15:22, 23 September 2009
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	{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}		{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}
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	~~{{hangon}}~~
	[[File:DB table.jpg\|right]]		[[File:DB table.jpg\|right]]

← Older revision		Revision as of 12:47, 23 September 2009
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	{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}		{{dated prod\|concern = This article seems superfluous as it consists of a definition from the main article [[Decibel]], some basic calculus and a table of logarithms, which is unnecessary in the age of calculators.\|month = September\|day = 17\|year = 2009\|time = 12:33\|timestamp = 20090917123319}}
	<!-- Do not use the "dated prod" template directly; the above line is generated by "subst:prod\|reason" -->		<!-- Do not use the "dated prod" template directly; the above line is generated by "subst:prod\|reason" -->

			{{hangon}}
	[[File:DB table.jpg\|right]]		[[File:DB table.jpg\|right]]