MATLAB: Goertzel routine bounds

Signal Processing Toolbox

Why Goertzel algorithm does not accept argument 'N+1' for FFT index ?

Goertzel accepts only integer argument for the FFT index number over the closed interval [1,N]

The option to specify that the DC frequency be at the center of the frequency axis is not available in the Signal Processing Toolbox.

To work around this issue, pass the frequency vector in the call to the SPECTROGRAM function like this:

NFFT = 128;
f_vec = [-floor(NFFT/2) : ceil(NFFT/2)-1] * Fs/NFFT;
spectrogram(x,hamming(128),64,f_vec,Fs);

Please refer to the section "*Legacy Code Tool Function Specification Rules*" in the documentation:

"You can specify argument dimensions with expressions that use the following:

In R2019b, it works with:

def.OutputFcnSpec = 'myCfun(single u1[],uint16 u2, single u3, single u4, single u5[], single y1[numel(u1)])'

In a release older than R2016b you can use 'single y1[size(u1,1)]' instead of 'numel':

def.OutputFcnSpec = 'myCfun(single u1[],uint16 u2, single u3, single u4, single u5[], *single y1[size(u1,1)]*)'