question: public static double [ ] computeLogAmplitudeSpectrum ( final double [ ] signal ) { double [ ] spectrum = computeAmplitudeSpectrum ( signal ) ; for ( int i = 0 ; i < spectrum . length ; i ++ ) { spectrum [ i ] = Math . log ( spectrum [ i ] ) ; } return spectrum ; }
target:  Convenience method for computing the log amplitude spectrum of a real signal. The signal can be of any length; internally, zeroes will be added if signal length is not a power of two.