[FieldTrip] ft_freqanalysis :: Warning: output frequencies are different from input frequencies

[Ana Pesquita]

Hello all,

I having difficulties with ft_freqanalysis.

*1) Problem:*
I am trying to compute frequencies at 0.1 Hz steps between 4 and 120 Hz.
But I am getting the following Warning back:

"Warning: output frequencies are different from input frequencies,
multiples of the same bin were requested but not given
trial 1, frequency 28 (129.57 Hz), 1 tapers
the call to "ft_freqanalysis" took 0 seconds"

And the frequency output is only of 28 different frequency values.

*2) Procedure:*
I am feeding in a structure to the  ft_freqanalysis with the following
characteristics:
svd_cd  struct with fields
    trialinfo: 'Int'
        trial: {[1×301 double]}
        label: {'MISC004xSVD'}
         time: {[1×301 double]}

This is my fieldtrip cal for frequency analysis:
%Compute FT
cfg = [];
cfg.output = 'pow';
cfg.taper = 'hanning';
cfg.method = 'mtmconvol';
cfg.foi          =  40:0.1:130;
cfg.t_ftimwin    =  5 ./cfg.foi ;
cfg.toi          = [-0.150 : 0.01: 0.150];
cfg.keeptrials = 'no';
tfr4 = ft_freqanalysis(cfg, svd_cd);

And the result:
tfr4 =

  struct with fields:

        label: {'MISC004xSVD'}
       dimord: 'chan_freq_time'
         freq: [1×28 double]
         time: [1×31 double]
    powspctrm: [1×28×31 double]
          cfg: [1×1 struct]

*3) Question:*
Can you identify why I can't get back the same number of output frequencies
as I am requesting in the cfg.foi request? Is there a way to get around
this?

Hope everyone is doing well : )
Many thanks in advance for your help!

Ana Pesquita
Postdoctoral Researcher
Center for Human Brain Health
University Of Birmingham, UK
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