ABSTRACT
The ARMA models discussed in Chapter 3 are used extensively for modeling stationary time series data and finding corresponding forecasts and spectral estimates. In this chapter, we discuss two other types of models that are also used to model stationary data. In Section 4.1, we discuss the harmonic models and harmonic signal-plus-noise models that are widely used in the engineering field. Section 4.2 discusses the autoregressive conditional heteroscedasticity (ARCH) models and the generalized ARCH (GARCH) models that have been developed in the field of econometrics.
