Effects in the z-Domain
摘要
This chapter analyzes how core multirate operations—sampling (with and without zero removal), modulation, and time reversal—map into the z-domain. The z-transform generalizes the discrete-time Fourier transform (DTFT) by extending analysis off the unit circle, exposing pole–zero geometry and enabling compact, algebraic descriptions of aliasing (via rotations), frequency-axis scaling (via exponent changes), spectral shifts (via rotations), and time reversal (via \(z \mapsto z^{-1}\) ). These identities are central to perfect reconstruction filter banks and wavelet systems.