Soner Bekleric Title of Thesis: Nonlinear Prediction via Volterra Ser
Soner Bekleric Title of Thesis: Nonlinear Prediction via Volterra Ser
Soner Bekleric Title of Thesis: Nonlinear Prediction via Volterra Ser
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2.3. LINEAR PREDICTION 16<br />
∂ρ fb<br />
p<br />
∂Rekp<br />
+ i ∂ρfb p<br />
∂Imkp<br />
= 0 (2.25)<br />
where Re and Im are real and imaginary parts, respectively, <strong>of</strong> the complex deriva-<br />
tive. A least squares solution ensures a solution for prediction coefficients, kp as<br />
follows:<br />
kp =<br />
where ∗ is the complex conjugation.<br />
−2 N n=p+1 ε f<br />
p−1(n)εb∗ p−1(n − 1)<br />
Nn=p+1 |ε f<br />
p−1(n)| 2 + N n=p+1 |εb p−1(n − 1)| 2<br />
(2.26)<br />
2.3.4 Computing the AR coefficients without limiting the<br />
aperture<br />
The Yule-Walker and Burg algorithms are <strong>of</strong>ten used in signal processing algorithms<br />
for their computational efficiency at the time <strong>of</strong> computing prediction error coeffi-<br />
cients. In what follows I will provide a method that I have introduced in order to<br />
solve for the coefficients <strong>of</strong> the linear prediction problem using only the data that<br />
are available. In other words, I will avoid creation <strong>of</strong> the correlation matrix and<br />
directly posed the problem as a least-squares problem.<br />
Consider a filter length p = 3 and a time series <strong>of</strong> length N = 7. Using equations<br />
(2.12) and (2.13) I can write the following equations: