--- a/scripts/signal/arch_rnd.m
+++ b/scripts/signal/arch_rnd.m
@@ -41,7 +41,7 @@
 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
 ## Description: Simulate an ARCH process
 
-function y = arch_rnd (a, b, T)
+function y = arch_rnd (a, b, t)
 
   if (nargin != 3)
     print_usage ();
@@ -50,7 +50,7 @@
   if (! ((min (size (a)) == 1) && (min (size (b)) == 1)))
     error ("arch_rnd: a and b must both be scalars or vectors");
   endif
-  if (! (isscalar (T) && (T > 0) && (rem (T, 1) == 0)))
+  if (! (isscalar (t) && (t > 0) && (rem (t, 1) == 0)))
     error ("arch_rnd: T must be a positive integer");
   endif
 
@@ -72,17 +72,17 @@
     b  = [b, 0];
     lb = lb + 1;
   endif
-  M  = max([la, lb]);
+  m  = max([la, lb]);
 
-  e  = zeros (T, 1);
-  h  = zeros (T, 1);
-  y  = zeros (T, 1);
+  e  = zeros (t, 1);
+  h  = zeros (t, 1);
+  y  = zeros (t, 1);
 
   h(1) = a(1);
   e(1) = sqrt (h(1)) * randn;
   y(1) = b(1) + e(1);
 
-  for t = 2:M
+  for t = 2:m
     ta   = min ([t, la]);
     h(t) = a(1) + a(2:ta) * e(t-ta+1:t-1).^2;
     e(t) = sqrt (h(t)) * randn;
@@ -90,14 +90,14 @@
     y(t) = b(1) + b(2:tb) * y(t-tb+1:t-1) + e(t);
   endfor
 
-  if (T > M)
-    for t = M+1:T
+  if (t > m)
+    for t = m+1:t
       h(t) = a(1) + a(2:la) * e(t-la+1:t-1).^2;
       e(t) = sqrt (h(t)) * randn;
       y(t) = b(1) + b(2:lb) * y(t-tb+1:t-1) + e(t);
     endfor
   endif
 
-  y = y(1:T);
+  y = y(1:t);
 
 endfunction