Spectral Analysis of Signals In most cases,ga(t)is defined for-oo<t<oo Thus,gn is of infinite extent,and defined for -co<n<oo Hence,ga(t)is first passed through an analog anti-aliasing filter whose output is then sampled to generate gn Assumptions:(1)Effect of aliasing can be ignored,(2)A/D conversion noise can be neglectedSpectral Analysis of Signals • In most cases, ga(t) is defined for-∞<t<∞ • Thus, g[n] is of infinite extent, and defined for -∞<n<∞ • Hence, ga(t) is first passed through an analog anti-aliasing filter whose output is then sampled to generate g[n] • Assumptions: (1) Effect of aliasing can be ignored, (2) A/D conversion noise can be neglected