convert signal curve into straight line

hello everyone

i want to ask something

i have signal plot like this

from this plot, i want to convert the curve into straight line with this formula : 1/√f

here is my code :

global X;
global R;
R = plot(B, A);
X = gca;
global freq;
global point;

X.Scale = 'log';
  int X p1 p2;
  double( 'froot(116)' )
  freq('116')
  val('116')
  point('116');
  double val1 val2; result; %#ok<VUNUS,NODEF>

    for X = 0
        X < 116 -1; %#ok
        for R = 0 : 116 -1;
      froot(X) = 8e-3 + (100e-3)/116.0*X; %#ok<AGROW>
      freq(X)  = (1.0/froot(X))*(1.0/froot(X)); 
      point(X) = 116.0*freq(X)/20000.0; %#ok<AGROW>
        p1 = trunc(int(point(X)));
        p2 = p1+1;
        val1 = val(p1);
        val2 = val(p2);
        result = val1+(val2-val1)/(p2-p1)*(point(X)-p1); %#ok<NASGU>
        end
    end
  guidata(hObject,handles);
  axes(handles.axes3); %#ok
  plot(R);
  msgbox('Transform SUCCESSFUL !');

please tell me if my code is wrong or not.

thanks

[Image Analyst]

I don't know. You didn't give us your data. We can't run your program. So you tell us. Does it look right to you?

[Evan Weking]

sorry about that,

this is my data for the program

i'm really sorry for before, thanks

[Star Strider]

That’s you .m file, not your data.

Answer 1

[Walter Roberson]

int X p1 p2;

in MATLAB means the same as

int('X', 'p1', 'p2')

which would attempt to find a function int that took character strings as input. It probably would not find one.

double( 'froot(116)' )

means to take the string 'froot(116)' and convert each character into its numeric encoding, such as 'f' being character #102. Then, the result of that conversion would be displayed because there is no semi-colon on the end of the line.

double val1 val2; result; %#ok<VUNUS,NODEF>

would be the same as

double('val', 'val2');
result;

which would get you an error message because double() only expects on argument.

freq('116')

would attempt to index the variable freq at [49, 49, 54] and display the result.

All in all, I think it likely that your code is in error. It appears that you attempted to convert from some other programming language.