Chapter 1 Continuous-time Signals and systems
Chapter 1 Continuous-time Signals and Systems
§11 Introduction Any problems about signal analyses and processing may be thought of letting signals trough systems. f(t) h(t) y(t) o From f(t) and h(t), find y(t), Signal processing o From f(t)and y(t, find h(t, System design o From y(t h(t), find f(t), Signal reconstruction
§1.1 Introduction Any problems about signal analyses and processing may be thought of letting signals trough systems. h(t) f(t) y(t) ❖From f(t) and h(t)，find y(t)， Signal processing ❖From f(t) and y(t) ，find h(t) ，System design ❖From y(t) and h(t)，find f(t) ， Signal reconstruction
§11 Introduction There are so many different signals and systems that it is impossible to describe them e one by one .The best approach is to represent the signal as a combination of some kind of most simplest signals which will pass though the system and produce a response. Combine the responses of alll simplest signals, which is the system response of the original signal .This is the basic method to study the signal analyses and processing
§1.1 Introduction ❖There are so many different signals and systems that it is impossible to describe them one by one ❖The best approach is to represent the signal as a combination of some kind of most simplest signals which will pass though the system and produce a response. Combine the responses of all simplest signals, which is the system response of the original signal. ❖This is the basic method to study the signal analyses and processing
s 1.2 Continue-time Signal . B All signals are thought of as a pattern of e variations in time and represented as a time function f(t) In the real-world. any signal has a start Let the start as t0 that means f(t)=0t<0 Call the signal causal
§1.2 Continue-time Signal ❖All signals are thought of as a pattern of variations in time and represented as a time function f(t). ❖In the real-world, any signal has a start. Let the start as t=0 that means f(t) = 0 t<0 Call the signal causal
Typical signals and their representation . Unit Step u(t(in our textbook u(t)) ult) t>0 0t<0 u(t) u(t) is basic causal signal, multiply which with any non-causal signal to get causal signal
Typical signals and their representation ❖Unit Step u(t) (in our textbook (t)) 1 0 0 0 ( ) = t t u t u(t) 1 0 t u(t- t0 ) 1 0 t t 0 ❖u(t) is basic causal signal, multiply which with any non-causal signal to get causal signal