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−% WELCHSCALE scales the output of welch to be in the required units
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−%
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−% $Id: welchscale.m,v 1.1 2011/12/01 09:41:22 hewitson Exp $
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−%
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−
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−function [yy, dyy, info] = welchscale(xx, dxx, win, fs, norm, inunits)
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−  
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−  nfft = length(win);
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−  S1   = sum(win);
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−  S2   = sum(win.^2);
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−  enbw = fs * S2 / (S1*S1);
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−  
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−  if isempty(norm)
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−    norm = 'None';
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−  end
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−  switch lower(norm)
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−    case 'asd'
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−      yy = sqrt(xx);
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−      if isempty(dxx)
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−        dyy = dxx;
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−      else
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−        dyy = 1./2./sqrt(xx) .* dxx;
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−      end
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−      info.units = inunits ./ unit('Hz^0.5');
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−    case 'psd'
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−      yy = xx;
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−      dyy = dxx;
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−      info.units = inunits.^2/unit('Hz');
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−    case 'as'
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−      yy = sqrt(xx * enbw);
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−      if isempty(dxx)
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−        dyy = dxx;
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−      else
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−        dyy = 1./2./sqrt(xx) .* dxx * enbw;
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−      end
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−      info.units = inunits;
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−    case 'ps'
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−      yy = xx * enbw;
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−      dyy = dxx * enbw;
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−      info.units = inunits.^2;
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−    case 'none'
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−      yy = xx;
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−      dyy = dxx;
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−      info.units = inunits;
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−    otherwise
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−      error('Unknown normalisation');
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−  end
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−  
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−  info.nfft = nfft;
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−  info.enbw = enbw;
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−  info.norm = norm;
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−  
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−end
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−