8.2 Estimation of All-Pole Models 8.2.1 Direct Structures 8.2.2 Lattice Structures 8.2.3 Maximum Entropy Method 8.2.4 Excitations with Line Spectra 21 21 8.2 Estimation of All-Pole Models 8.2.1 Direct Structures 8.2.2 Lattice Structures 8.2.3 Maximum Entropy Method 8.2.4 Excitations with Line Spectra