Bài giảng Xử lý tín hiệu số: Signal and System in Time Domain - Ngô Quốc Cường (ĐH Sư phạm Kỹ thuật)

Bài giảng "Xử lý tín hiệu số: Signal and System in Time Domain" cung cấp cho người học các kiến thức: Discrete time signals, discrete time systems, LTI systems. Mời các bạn cùng tham khảo nội dung chi tiết.
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Bài giảng Xử lý tín hiệu số: Signal and System in Time Domain - Ngô Quốc Cường (ĐH Sư phạm Kỹ thuật) Xử lý tín hiệu số Signal and System in Time DomainNgô Quốc Cườngngoquoccuong175@gmail.com Ngô Quốc Cườngsites.google.com/a/hcmute.edu.vn/ngoquoccuong Signal and System in Time Domain• Discrete time signals• Discrete time systems• LTI systems 2 2.1 Discrete - time signals• A discrete time signal x(n) is a function of an independent variable that is integer. 3 2.1 Discrete - time signals• Alternative representation of discrete time signal: 4 2.1 Discrete - time signals• Alternative representation of discrete time signal: 52.1.1 Some elementary signals 62.1.1 Some elementary signals 72.1.1 Some elementary signals 82.1.1 Some elementary signals 9 2.1.2 Classification of discrete time signal• Energy signals and power signal – The energy E of a signal x(n) is given: – If E is finite, x(n) is call an energy signal. 10 2.1.2 Classification of discrete time signal• Energy signals and power signal – The average power P of a signal x(n) is defined: – If P is finite (and nonzero), x(n) is called a power signal. 11 2.1.2 Classification of discrete time signal• Energy signals and power signal – Example: the average power of the unit step signal is: 12 2.1.2 Classification of discrete time signal• Periodic signals and aperiodic signals – A signal x(n) is periodic with period N (N >0) if and only if 13 2.1.2 Classification of discrete time signal• Symmetric (even) and antisymmetric (odd) signals – A real value signal x(n) is call symmetric if – A signal is call antisymmetric if 14 2.1.2 Classification of discrete time signal• Symmetric (even) and antisymmetric (odd) signals 15 2.1.2 Classification of discrete time signal– The even signal component is formed by adding x(n) to x(- n) and dividing by 2.– Odd signal component 16 2.1.3 Simple manipulations of signals• Transformation of time – A signal x(n) may be shifted by replacing n bay n-k. • k is positive number: delay • k is negative number: advance – Folding: replace n by -n – Time scaling: replace n by cn (c is an integer) 17 2.1.3 Simple manipulations of signals• Transformation of time – Find x(n-3) and x(n+2) of x(n) 18 2.1.3 Simple manipulations of signals• Transformation of time – Find x(-n) and x(-n+2) of x(n) 19 2.1.3 Simple manipulations of signals• Transformation of time – Show the graphical representation of y(n) = x(2n), where x(n) is 20