D.8.2 harminv output

The result returned by a call to

     library('harminv','hsolve')

with valid input (harminv input parameters) is a list of similar tuples of the form

     <(amplitude,frequency,decay,quality,error)...>

with all members being real valued except for the amplitudes, which are complex. Each tuple describes a function of the form

     f(t) = A * sin (frequency * t + P) * exp (-decay * t)

such that the summation of these functions approximates the original given signal (harminv input parameters). The real amplitude A and phase P are given by the modulus and argument of the complex amplitude returned in the result,

     A = library('complex','cabs') amplitude
     P = library('complex','carg') amplitude

in terms of the complex library functions (complex). The error values are measures of the goodness of fit, and the quality factors are defined as

     quality = (pi * |frequency| / decay)

It may be useful in some applications to ignore components with quality factors outside of a certain range.