Programmer Guide/Command Reference/EVAL/asp2osp: Difference between revisions

Revision as of 14:26, 13 April 2011

Convert an amplitude spectrum to an order spectrum.

Usage

asp2osp(a, df, f1 {, do, no, oini})

asp2osp(a, f, f1 {, do, no, oini})

a: amplitude or power spectrum (vector)
df: frequency resolution of the spectrum in Hz (scalar); 0 < df, f[i]=i*df
f: frequency scale of the spectrum in Hz (vector)
f1: frequency of the 1st order in Hz
do: resolution of the order spectrum; 0 < do (default=0.1)
no: length of the order spectrum; 2 < no (default=500)
oini: amplitude value for order spectrum initialization (default=0)

Description 1: The function implements a fast algorithm to convert a frequency spectrum a=f(f) into an order spectrum ao=f(f1,do). The algorithm uses interpolation (if a must be expanded) and maximum detection (if a must be compressed) to approximate the values of the order spectrum. The frequency range of the order spectrum is limited to 0 to f1*do*no. All bins of o outside the frequency range of a (0..df*nrow(a)-1 or f[0]..f[nrow(a)-1] are set the value oini.
Result: The order spectrum o (vector with no elements).

@@ Line 5: / Line 5: @@
 :<code>asp2osp(<var>a</var>, <var>f</var>, <var>f1</var> {, <var>do</var>, <var>no</var>, <var>oini</var>})</code>
 :;<var>a</var>:amplitude or power spectrum (vector)
-:;<var>df</var>:frequency resolution of the spectrum in Hz (scalar); 0 < ''df'', ''f''[i]=i*df)
+:;<var>df</var>:frequency resolution of the spectrum in Hz (scalar); 0 < ''df'', ''f''[i]=i*df
 :;<var>f</var>:frequency scale of the spectrum in Hz (vector)
 :;<var>f1</var>:frequency of the 1st order in Hz