Multitaper spectral estimation (pmtm.m)

Hi,

I was trying to use pmtm function but oddly it gives error. I have been using it a few months ago with no problem. Has anybody experienced something similar? Even with MATLAB example i cannot make it (tried in both 2013b and 2015a):

n = 0:319;
x = cos(pi/4*n)+randn(size(n));
pxx = pmtm(x);

The error is:

Error using dpss
Too many output arguments.

Error in pmtm>getEV (line 526)
   [E,V] = dpss(N,NW);

Error in pmtm>parseinputs (line 365)
[E,V,NW,indx,nfft_temp,varargin] = getEV(N,varargin{:});

Error in pmtm (line 152)
params = parseinputs(x,varargin{:});

Anybody, any idea please?

Answer 1

[Brian Neiswander]

I was able to run the code you posted in R2015a without an error. The error you see may be caused by a local "dpss" function that is interfering with the "dpss" function in MATLAB's Signal Processing Toolbox. Run the following statement in your MATLAB command window:

>>  which dpss

The output should display a location inside the Signal Processing Toolbox folder, such as:

<matlabroot>\toolbox\signal\signal\dpss.m

where <matlabroot> is the output of:

>>  matlabroot

If the location is not inside the Signal Processing Toolbox folder then there is a local function that is causing the problem. In this case, you can either rename the local "dpss" function or move it out of your MATLAB path.