Programmer Guide/Command Reference/EVAL/log2lin - Revision history

193.171.195.48 at 10:16, 21 April 2011

2011-04-21T10:16:01Z

← Older revision		Revision as of 12:16, 21 April 2011
Line 1:		Line 1:
	{{DISPLAYTITLE:lin2log , log2lin (alias: dB)}}		{{DISPLAYTITLE:lin2log , log2lin (alias: dB)}}
	Convert the elements of ''x'' to logarithmic values (e.g. dB) and vice versa.		Convert the elements of ''x'' to logarithmic values (e.g. dB) and vice versa.
	;Usage: ~~'''~~<code>lin2log(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code>		;Usage: <code>lin2log(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code>
	:~~'''~~<code>log2lin(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code>		:<code>log2lin(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code>
	:;<var>x</var>: a scalar, vector or matrix		:;<var>x</var>: a scalar, vector or matrix
	:;<var>ref</var>: the reference value; must be a positive number (default=1)		:;<var>ref</var>: the reference value; must be a positive number (default=1)
Line 11:		Line 11:
	:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.		:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.

	;See also: [[~~Programmer_Guide/Command_Reference/EVAL~~/log\|log]], [[~~Programmer_Guide/Command_Reference/EVAL~~/exp\|exp]], [[~~Programmer_Guide/Command_Reference/EVAL~~/fft\|fft]], [[~~Programmer_Guide~~/~~Command_Reference/EVAL~~/~~cr2len~~\|~~cr2len~~]]		;See also: [[../log\|log]], [[../exp\|exp]], [[../fft\|fft]], [[../complex arithmetic\|complex arithmetic (cr2p, cp2r, cr2len)]]

			[[../#Functions\|<function list>]]


Line 23:		Line 25:
	$#sig := eval $#sig * db(6)		$#sig := eval $#sig * db(6)
	</pre>		</pre>

	~~[[Programmer_Guide/Command_Reference/EVAL#Functions\|<function list>]]~~

Toni at 14:37, 6 April 2011

2011-04-06T14:37:51Z

← Older revision		Revision as of 16:37, 6 April 2011
Line 12:		Line 12:

	;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]]		;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]]


	Example:		Example:

Toni at 13:54, 6 April 2011

2011-04-06T13:54:34Z

← Older revision		Revision as of 15:54, 6 April 2011
Line 11:		Line 11:
	:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.		:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.

	;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],		;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]]

	Example:		Example:

Toni at 13:51, 6 April 2011

2011-04-06T13:51:50Z

← Older revision		Revision as of 15:51, 6 April 2011
Line 6:		Line 6:
	:;<var>ref</var>: the reference value; must be a positive number (default=1)		:;<var>ref</var>: the reference value; must be a positive number (default=1)
	:;<var>fac</var>: the factor; must be a positive number (default=20)		:;<var>fac</var>: the factor; must be a positive number (default=20)
	;Result: The result ''r'' has the same type as ''x'' and contains the converted elements of ''x''.		;Result: The result ''r'' has the same type as ''x'' and contains the converted elements of ''x''. The following conversion algorithms are used:
	::lin2log: ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')		::'''lin2log''': ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')
	::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')		::'''log2lin''': ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')
	:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.		:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.

Toni at 13:47, 6 April 2011

2011-04-06T13:47:03Z

← Older revision		Revision as of 15:47, 6 April 2011
Line 9:		Line 9:
	::lin2log: ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')		::lin2log: ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')
	::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')		::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')
	:Note: The function ''dB'' is an alias for ''log2lin'' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.		:Note: The function '''dB''' is an alias for '''log2lin''' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.

	;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],		;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],
Line 18:		Line 18:
	#aref := set '20e-6' // reference value: 20 micro Pascal		#aref := set '20e-6' // reference value: 20 micro Pascal
	#logamp := eval lin2log(cr2len($#spe), $#aref) // the log. amplitude spectrum in dB		#logamp := eval lin2log(cr2len($#spe), $#aref) // the log. amplitude spectrum in dB

			// apply 6dB attenuation to the signal stored in the vector #sig
			$#sig := eval $#sig * db(6)
	</pre>		</pre>

	[[Programmer_Guide/Command_Reference/EVAL#Functions\|<function list>]]		[[Programmer_Guide/Command_Reference/EVAL#Functions\|<function list>]]

Toni at 13:45, 6 April 2011

2011-04-06T13:45:28Z

← Older revision		Revision as of 15:45, 6 April 2011
Line 1:		Line 1:
	{{DISPLAYTITLE:lin2log, log2lin}}		{{DISPLAYTITLE:lin2log , log2lin (alias: dB)}}
	Convert the elements of ''x'' to logarithmic values (e.g. dB) and vice versa.		Convert the elements of ''x'' to logarithmic values (e.g. dB) and vice versa.
	;Usage: '''<code>lin2log(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code>		;Usage: '''<code>lin2log(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code>
Line 9:		Line 9:
	::lin2log: ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')		::lin2log: ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')
	::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')		::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')
			:Note: The function ''dB'' is an alias for ''log2lin'' and is implemented for compatibility with the expressions used in the [[Programmer_Guide/Command_Reference/NUM\|NUM]] and [[Programmer_Guide/Command_Reference/INT\|INT]] command.

	;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],		;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],

Toni at 13:40, 6 April 2011

2011-04-06T13:40:12Z

← Older revision		Revision as of 15:40, 6 April 2011
Line 10:		Line 10:
	::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')		::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')

	;See also: [[Programmer_Guide/Command_Reference/EVAL/~~npow2~~\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],		;See also: [[Programmer_Guide/Command_Reference/EVAL/log\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],

	Example:		Example:

Toni at 13:38, 6 April 2011

2011-04-06T13:38:45Z

← Older revision		Revision as of 15:38, 6 April 2011
Line 10:		Line 10:
	::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')		::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')

	;See also: [[Programmer_Guide/Command_Reference/EVAL/npow2\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]]		;See also: [[Programmer_Guide/Command_Reference/EVAL/npow2\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]], [[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],
	[[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],
	Example:		Example:
	<pre>		<pre>

Toni at 13:38, 6 April 2011

2011-04-06T13:38:20Z

← Older revision		Revision as of 15:38, 6 April 2011
Line 11:		Line 11:

	;See also: [[Programmer_Guide/Command_Reference/EVAL/npow2\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]]		;See also: [[Programmer_Guide/Command_Reference/EVAL/npow2\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]]
			[[Programmer_Guide/Command_Reference/EVAL/fft\|fft]], [[Programmer_Guide/Command_Reference/EVAL/cr2len\|cr2len]],
	Example:		Example:
	<pre>		<pre>

Toni at 13:37, 6 April 2011

2011-04-06T13:37:32Z

← Older revision		Revision as of 15:37, 6 April 2011
Line 6:		Line 6:
	:;<var>ref</var>: the reference value; must be a positive number (default=1)		:;<var>ref</var>: the reference value; must be a positive number (default=1)
	:;<var>fac</var>: the factor; must be a positive number (default=20)		:;<var>fac</var>: the factor; must be a positive number (default=20)
	;Result: The result ''r'' has the same type as ''x'' and contains the converted elements of ''x''		;Result: The result ''r'' has the same type as ''x'' and contains the converted elements of ''x''.
	::lin2log: ''r''<sub>i,j</sub> = fac log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')		::lin2log: ''r''<sub>i,j</sub> = ''fac'' log<sub>10</sub>(''x''<sub>i,j</sub> / ''ref'')
	::log2lin: ''r''<sub>i,j</sub> = ref 10 ^ (''x''<sub>i,j</sub> / ''fac'')		::log2lin: ''r''<sub>i,j</sub> = ''ref'' 10 ^ (''x''<sub>i,j</sub> / ''fac'')

	;See also: [[Programmer_Guide/Command_Reference/EVAL/npow2\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]]		;See also: [[Programmer_Guide/Command_Reference/EVAL/npow2\|log]], [[Programmer_Guide/Command_Reference/EVAL/exp\|exp]]
Line 14:		Line 14:
	Example:		Example:
	<pre>		<pre>
	#a := ~~eval 20*log(2)~~ // ~~convert factor 2 to 6dB~~		// #spe is a vector containing a complex spectrum
	#b :~~= eval~~ 20*log(2,10) // same as above		#aref := set '20e-6' // reference value: 20 micro Pascal
	#c := eval ~~20*log~~(vv(2,~~10,20,50,100)~~)		#logamp := eval lin2log(cr2len($#spe), $#aref) // the log. amplitude spectrum in dB
	// ~~$#c = { 6~~.~~02, 20, 26.02, 33.98, 40 }~~
	</pre>		</pre>

	[[Programmer_Guide/Command_Reference/EVAL#Functions\|<function list>]]		[[Programmer_Guide/Command_Reference/EVAL#Functions\|<function list>]]