6.255 
Fig. 5.30a. Theoretical ARMA process ARMA(2.1). 
Fig. 5.30. Spectrum for ARMA(2.1) process (2) 
X,-0.3 Xe SP 0.4 X-2 = Ert 0.7€ tH1) Er: N[O, 1]. 
154 
