diff --git a/script_m/diff_plot.m b/script_m/diff_plot.m
index e88b75a..19bf93a 100755
--- a/script_m/diff_plot.m
+++ b/script_m/diff_plot.m
@@ -1,6 +1,8 @@
 function diff_plot(iir_out, Script_out,leg1,leg2,a)
 
-N = length(iir_out);
+N = min(length(iir_out),length(Script_out));
+iir_out = iir_out(1:N);
+Script_out = Script_out(1:N);
 n = 0:1:N-1;
 diff = iir_out-Script_out;