延安大学：《数字信号处理》课程PPT教学课件（DigitalSignal Processing，DSP）Chapter 1 Discrete-Time Signals and Systems

Chapter 1 Discrete-Time Signals and Systems

Chapter 1 Discrete-Time Signals and Systems

O To understand the theory of digital signal processing and design of discrete-time systems we need to know how to mathematically represent discrete-time signals and systems. Such representations can be either in the time-domain or in the frequency domain

⚫ To understand the theory of digital signal processing and design of discrete-time systems, we need to know how to mathematically represent discrete-time signals and systems. Such representations can be either in the time-domain or in the frequency domain

Content Introduction a Discrete-time signals a Discrete-time systems a Time-domain characterization of lti discrete-time systems Digitalization of Analog Digital

Content ◼ Introduction ◼ Discrete-time signals ◼ Discrete-time systems ◼ Time-domain characterization of LTI discrete-time systems ◼ Digitalization of Analog Digital

1. 1 Introduction O A signal is a function of independent variables Depending on the nature of the independent variables and value of the function defining the signal, various types of signals can be defined

1.1 Introduction ⚫ A signal is a function of independent variables. Depending on the nature of the independent variables and value of the function defining the signal, various types of signals can be defined

1. 1 Introduction o Classification of signals 1. Analog signal-A continuous-time signal with a continuous amplitude 2. Digital signal-a discrete-time signal with discrete-valued amplitudes represented by a finite number of digits

1.1 Introduction ⚫ Classification of signals 1. Analog signal—A continuous-time signal with a continuous amplitude. 2. Digital signal—A discrete-time signal with discrete-valued amplitudes represented by a finite number of digits

1. 1 Introduction o Classification of signals 3. Sampled-data signal--a discrete-time signal with a continuous-valued amplitude 4. Quantized boxcar signal-A continuous-time signal with discrete-valued amplitudes represented by a finite number of digits

1.1 Introduction ⚫ Classification of signals 3. Sampled-data signal--A discrete-time signal with a continuous-valued amplitude. 4. Quantized boxcar signal—A continuous-time signal with discrete-valued amplitudes represented by a finite number of digits

Timet Time. t Time, t · Figure 1.1:(a)A cvntinuous-time signal, (b) a digital signal, (c)a sampled-data signal, and(d)a quantized boxcar

1. 1 Introduction a Note: A continuous-time signal is defined at every instant of time. On the other hand, a discrete-time signal takes certain numerical values at specified discrete instants of time and between these specified instants of time the signal is not defined

1.1 Introduction  Note: A continuous-time signal is defined at every instant of time. On the other hand, a discrete-time signal takes certain numerical values at specified discrete instants of time, and between these specified instants of time, the signal is not defined

1.1 Introduction o Classification of signals Depending on the number of independent variable, the signal can be classified as a one-dimensional signal(speech a two-dimensional signal (image) a multidimensional signal(video)

1.1 Introduction ◆ Depending on the number of independent variable, the signal can be classified as  one-dimensional signal (speech)  two-dimensional signal (image)  multidimensional signal (video) ⚫ Classification of signals

1. 1 Introduce Classification of Signals Another classification of signals that depends on the certainty by which the signal can be uniquely describe a Deterministic signal a Random Signal

1.1 Introduce ◆ Another classification of signals that depends on the certainty by which the signal can be uniquely described.  Deterministic signal  Random signal ◼ Classification of Signals