--- a/fourier/gga.m
+++ b/fourier/gga.m
@@ -1,6 +1,7 @@
function c = gga(f,fvec,fs,dim)
%GGA Generalized Goertzel algorithm
-%   Usage:  c = gga(x,indvec)
+%   Usage:  c = gga(x,fvec)
+%           c = gga(x,fvec,fs)
%
%   Input parameters:
%         x      : Input data.
@@ -11,14 +12,14 @@
%         c      : Coefficient vector.
%
%   c=gga(f,fvec) computes the discrete-time fourier transform DTFT of
-%   *f* at frequencies in fvec as $c(k)=F(2*pi*fvec(k))$ where
-%   $F=DTFT(f)$, $k=1,\dots\K$ and K=length(fvec) using the generalized
+%   *f* at frequencies in fvec as $c(k)=F(2\pi f_{vec}(k))$ where
+%   $F=DTFT(f)$, $k=1,\dots K$ and K=length(fvec) using the generalized
%   second-order Goertzel algorithm. Thanks to the generalization, values
%   in fvec can be arbitrary numbers in range $0-1$ and not restricted to
-%   $l/Ls$, $l=0,\dots\Ls-1$ (usual DFT samples) as the original Goertzel
+%   $l/Ls$, $l=0,\dots Ls-1$ (usual DFT samples) as the original Goertzel
%   algorithm is. *Ls* is the length of the first non-singleton dimension
%   of *f*. If indvec is empty or ommited, indvec is assumed to be
-%   (0:Ls-1)/L and results in the same output as fft.
+%   (0:Ls-1)/Ls and results in the same output as fft.
%
%   c=gga(f,fvec,fs) computes the same with frequencies relative to *fs*.
%