mtspecgramc_slow.m 4.4 KB

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  1. function [S,t,f,Serr]=mtspecgramc_slow(data,movingwin,params)
  2. % Multi-taper time-frequency spectrum - continuous process
  3. %
  4. % Usage:
  5. % [S,t,f,Serr]=mtspecgramc(data,movingwin,params)
  6. % Input:
  7. % Note units have to be consistent. Thus, if movingwin is in seconds, Fs
  8. % has to be in Hz. see chronux.m for more information.
  9. % data (in form samples x channels/trials) -- required
  10. % movingwin (in the form [window winstep] i.e length of moving
  11. % window and step size)
  12. % Note that units here have
  13. % to be consistent with
  14. % units of Fs - required
  15. % params: structure with fields tapers, pad, Fs, fpass, err, trialave
  16. % - optional
  17. % tapers : precalculated tapers from dpss or in the one of the following
  18. % forms:
  19. % (1) A numeric vector [TW K] where TW is the
  20. % time-bandwidth product and K is the number of
  21. % tapers to be used (less than or equal to
  22. % 2TW-1).
  23. % (2) A numeric vector [W T p] where W is the
  24. % bandwidth, T is the duration of the data and p
  25. % is an integer such that 2TW-p tapers are used. In
  26. % this form there is no default i.e. to specify
  27. % the bandwidth, you have to specify T and p as
  28. % well. Note that the units of W and T have to be
  29. % consistent: if W is in Hz, T must be in seconds
  30. % and vice versa. Note that these units must also
  31. % be consistent with the units of params.Fs: W can
  32. % be in Hz if and only if params.Fs is in Hz.
  33. % The default is to use form 1 with TW=3 and K=5
  34. % Note that T has to be equal to movingwin(1).
  35. %
  36. % pad (padding factor for the FFT) - optional. Defaults to 0.
  37. % e.g. For N = 500, if PAD = 0, we pad the FFT
  38. % to 512 points; if PAD = 2, we pad the FFT
  39. % to 2048 points, etc.
  40. % Fs (sampling frequency) - optional. Default 1.
  41. % fpass (frequency band to be used in the calculation in the form
  42. % [fmin fmax])- optional.
  43. % Default all frequencies between 0 and Fs/2
  44. % err (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
  45. % [0 p] or 0 - no error bars) - optional. Default 0.
  46. % trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0
  47. % Output:
  48. % S (spectrum in form time x frequency x channels/trials if trialave=0; in the form time x frequency if trialave=1)
  49. % t (times)
  50. % f (frequencies)
  51. % Serr (error bars) only for err(1)>=1
  52. if nargin < 2; error('Need data and window parameters'); end;
  53. if nargin < 3; params=[]; end;
  54. if length(params.tapers)==3 & movingwin(1)~=params.tapers(2);
  55. error('Duration of data in params.tapers is inconsistent with movingwin(1), modify params.tapers(2) to proceed')
  56. end
  57. [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
  58. if nargout > 3 && err(1)==0;
  59. % Cannot compute error bars with err(1)=0. change params and run again.
  60. error('When Serr is desired, err(1) has to be non-zero.');
  61. end;
  62. data=change_row_to_column(data);
  63. N=size(data,1);
  64. Nwin=round(Fs*movingwin(1)); % number of samples in window
  65. Nstep=round(movingwin(2)*Fs); % number of samples to step through
  66. nfft=2^(nextpow2(Nwin)+pad);
  67. f=getfgrid(Fs,nfft,fpass);
  68. params.tapers=dpsschk(tapers,Nwin,Fs); % check tapers
  69. winstart=1:Nstep:N-Nwin+1;
  70. nw=length(winstart);
  71. if trialave
  72. S = zeros(nw,length(f));
  73. else
  74. %S = zeros(nw,length(f),size(data,2));
  75. end
  76. for n=1:nw;
  77. indx=winstart(n):winstart(n)+Nwin-1;
  78. datawin=data(indx,:);
  79. if nargout==4
  80. [s,f,serr]=mtspectrumc(datawin,params);
  81. Serr(1,n,:,:)=squeeze(serr(1,:,:));
  82. Serr(2,n,:,:)=squeeze(serr(2,:,:));
  83. else
  84. [s,f]=mtspectrumc(datawin,params);
  85. end
  86. S(n,:,:)=s;
  87. end;
  88. S=squeeze(S);
  89. if nargout==4;Serr=squeeze(Serr);end;
  90. winmid=winstart+round(Nwin/2);
  91. t=winmid/Fs;