1 files changed, 37 insertions, 28 deletions
diff --git a/macros/flattopwin.sci b/macros/flattopwin.sci
index 41250c1..905a1be 100644
--- a/macros/flattopwin.sci
+++ b/macros/flattopwin.sci
@@ -1,47 +1,56 @@
 function w = flattopwin (m, opt)
+
 //This function returns the filter coefficients of a Flat Top window.
 //Calling Sequence
 //w = flattopwin (m)
 //w = flattopwin (m, opt)
-//Parameters 
+//Parameters
 //m: positive integer value
 //opt: string value, takes in "periodic" or "symmetric"
-//w: output variable, vector of real numbers 
+//w: output variable, vector of real numbers
 //Description
 //This is an Octave function.
 //This function returns the filter coefficients of a Flat Top window of length m supplied as input, to the output vector w.
 //The second parameter can take the values "periodic" or "symmetric", depending on which the corresponding form of window is returned. The default is symmetric.
-//This window has low pass-band ripple but a high bandwidth. 
+//This window has low pass-band ripple but a high bandwidth.
 //Examples
 //flattopwin(8,"periodic")
 //ans  =
-//    0.0009051  
-//  - 0.0264124  
-//  - 0.0555580  
-//    0.4435496  
-//    1.         
-//    0.4435496  
-//  - 0.0555580  
-//  - 0.0264124  
-funcprot(0);
-rhs = argn(2)
-if(rhs<1 | rhs>2)
-error("Wrong number of input arguments.")
-end
+//    0.0009051
+//  - 0.0264124
+//  - 0.0555580
+//    0.4435496
+//    1.
+//    0.4435496
+//  - 0.0555580
+//  - 0.0264124
 
-if(rhs==2)
-	if(opt~="periodic" & opt~="symmetric")
-	error("Window type should be periodic or symmetric.")
-	end
-end
+ funcprot(0);
+    rhs= argn(2);
 
-	select(rhs)
-	case 1 then
-	w = callOctave("flattopwin",m)
-	case 2 then
-	w = callOctave("flattopwin",m,opt)
-	end
-endfunction
+  if (rhs < 1 | rhs > 2)
+    error("Wrong Number of input arguments");
+  elseif (~ (isscalar (m) & (m == fix (m)) & (m > 0)))
+    error ("flattopwin: M must be a positive integer");
+  end
 
+  N = m - 1;
+  if (rhs == 2)
+    select (opt)
+      case "periodic"
+        N = m;
+      case "symmetric"
+        N = m - 1;
+      else
+        error ("flattopwin: window type must be either periodic or symmetric");
+    end
+  end
 
+  if (m == 1)
+    w = 1;
+  else
+    x = 2*%pi*[0:m-1]'/N;
+    w = (1-1.93*cos(x)+1.29*cos(2*x)-0.388*cos(3*x)+0.0322*cos(4*x))/4.6402;
+  end
 
+endfunction