Week 12. Chapter 11, Sampling and Reconstruction 1.Sampling and aliasing 2.Reconstruction 3.The Shannon-Nyquist theorem
1. Sampling
Sampling a sinusoid
Topics/sampling/aliasing Topics/sampling/images Topics/sampling/Moire Patterns Topics/sampling/fonts
2 Reconstruction Not unique
Approach
Examples of reconstruction filters kT Zero-order hold h 0T 1 1. kT t First-order h 0T 1 -T 2. kT t
t raised-cosine h 0T 1 -T 3.
4. Ideal interpolation
Understanding is through frequency domain
see later
Example /T 0
Shannon-Nyquist Theorem
Example
1/2 T T 1/2T (a) (b) 1/2
Two remaining facts