deriv_line

 r = DERIV_LINE(r,fsamp,filt) differentiation with the option to filter.

 ARGUMENTS
  r        ...  Matrix data (n x 1 or n x3)
  fsamp    ...  Sampling rate of signal
  filt     ...  Filter options (boolean)
                filt = 0 or false: do not filter (default)
                filt = 1 or true: filter data using 4th ord butt low-pass with 10 Hz cutoff
                filt = struct: filter according to struc fields (see bmech_filter)

 RETURNS
  r        ...  Differentiated matrix data

 NOTES
 - use the following example to test the differentiation method
     t = (0:0.001:1)';
     x = sin(2*pi*t);
     dx1 = 2*pi*cos(2*pi*t);
     dx2 = deriv_line(x,1000,0);
     plot(dx1)
     hold on
     plot(dx2,'r')

 See also bmech_deriv, deriv_data, gradient, filter_line