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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:

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