Programmer Guide/Command Reference/EVAL/log2lin: Difference between revisions
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:Default is <code>20</code>. | :Default is <code>20</code>. | ||
{{DISPLAYTITLE:lin2log, log2lin}} | |||
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> | |||
:'''<code>log2lin(<var>x</var> {, <var>ref</var> {, <var>fac</var>}})</code> | |||
:;<var>x</var>: a scalar, vector or matrix | |||
:;<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) | |||
;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'') | |||
::*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]] | |||
Example: | |||
<pre> | |||
#a := eval 20*log(2) // convert factor 2 to 6dB | |||
#b := eval 20*log(2,10) // same as above | |||
#c := eval 20*log(vv(2,10,20,50,100)) | |||
// $#c = { 6.02, 20, 26.02, 33.98, 40 } | |||
</pre> | |||
[[Programmer_Guide/Command_Reference/EVAL#Functions|<function list>]] | |||
Revision as of 15:33, 6 April 2011
log2lin
Logarithmic to linear conversion where x -> ref * 10 ^ (x / fac)
Usage:
log2lin(x, ref, fac)
Parameters:
- ref
- Default is
1.
- fac
- Default is
20.
Warning: Display title "lin2log, log2lin" overrides earlier display title "log2lin". Convert the elements of x to logarithmic values (e.g. dB) and vice versa.
- Usage
lin2log(x {, ref {, fac}})log2lin(x {, ref {, fac}})- x
- a scalar, vector or matrix
- ref
- the reference value; must be a positive number (default=1)
- fac
- 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
- lin2log: ri,j = fac * log10(xi,j / ref)
- log2lin: ri,j = ref * 10 ^ (xi,j / fac)
Example:
#a := eval 20*log(2) // convert factor 2 to 6dB
#b := eval 20*log(2,10) // same as above
#c := eval 20*log(vv(2,10,20,50,100))
// $#c = { 6.02, 20, 26.02, 33.98, 40 }
