diff --git a/ofdm/fdet_eval.m b/ofdm/fdet_eval.m
new file mode 100644
index 0000000..fc463d2
--- /dev/null
+++ b/ofdm/fdet_eval.m
@@ -0,0 +1,41 @@
+function fdet_eval()
+
+fs = 48000;
+N = 1024;
+
+f_true = 2000.000;
+phi_true = 1;
+
+x_true = exp(j*(2*pi*f_true/fs*(0:N-1)'+phi_true));
+
+% Initial guess
+X = fft(x_true, N);
+[v maxk] = max(abs(X));
+f_est = (maxk-1)*fs/N
+phi_est = angle(x_true(1));
+mu = 1.0;
+
+for k=1:500
+    x_est = exp(-j*(2*pi*f_est/fs*(0:N-1)'+phi_est));
+    dmod(k) = sum(x_true.*x_est);
+    err(k) = sign(imag(dmod(k)))*(1-real(dmod(k)/abs(dmod(k))))^.5;
+    f_est = f_est + mu*err(k);
+	f(k) = f_est;
+end;
+
+f_true = f_true
+f_est = f_est
+
+close all;
+subplot(3,1,1)
+plot(1:lge(f), 1-real(dmod)./abs(dmod), 1:lge(f), imag(dmod)./abs(dmod)); grid;
+
+subplot(3,1,2)
+plot(1:lge(f), err, '-*'); grid;
+
+subplot(3,1,3)
+plot(1:lge(f), f); grid;
+
+
+figure;
+plot(1:lge(f), sign(imag(dmod(k))).*(abs(dmod)-real(dmod))./abs(dmod)); grid;
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