dev tf

src/transfer_functions.jl

+using DSP
+function tfest(y,u)
+    Cyu = xcorr(y,u)
+    Cuu = xcorr(u,u)
+    Syu = welch_pgram(Cyu)
+    Suu = welch_pgram(Cuu)
+    return H = TF(Syu.power./Suu.power,Syu.freq)
+
+end
+
+
+N = 200000;
+u = randn(N);
+y = filt(ones(30),30,u);
+
+H = tfest(y,u);
+loglog(H.f,abs(H.P))