diff --git a/analyse.sh b/analyse.sh
new file mode 100644
index 0000000..20d602b
--- /dev/null
+++ b/analyse.sh
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+
diff --git a/scripts/templates/timelag_compare.gp b/scripts/templates/timelag_compare.gp
index 7934b0d..446b60a 100644
--- a/scripts/templates/timelag_compare.gp
+++ b/scripts/templates/timelag_compare.gp
@@ -11,7 +11,7 @@ set logscale x
 
 set ylabel "Lag [days]"
 #set yrange [%YMIN:%YMAX]
-set yrange [-5:7]
+#set yrange [-5:7]
 set key outside
 set key center bottom
 
diff --git a/scripts/tophat_fft.pl b/scripts/tophat_fft.pl
new file mode 100755
index 0000000..f6b4567
--- /dev/null
+++ b/scripts/tophat_fft.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+
+use feature say;
+use utf8; 
+use PDL::FFT;
+
+my $PI = 3.1415926539;
+my $N = 64;
+my ($series, $other_series);
+for (my $k=0; $k<$N; $k++) {
+  $series->[$k] = sin(4*$k*$PI/$N) + cos(6*$k*$PI/$N);
+}
+my $fft = new Math::FFT($series);
+my $coeff = $fft->rdft();
+my $spectrum = $fft->spctrm;
+my $original_data = $fft->invrdft($coeff);
+
+for (my $k=0; $k<$N; $k++) {
+  $other_series->[$k] = sin(16*$k*$PI/$N) + cos(8*$k*$PI/$N);
+}
+my $other_fft = $fft->clone($other_series);
+my $other_coeff = $other_fft->rdft();
+my $correlation = $fft->correl($other_fft);
\ No newline at end of file