电子科技大学信号与系统第一章信号的表示方法

电子科技大学信号与系统第一章知识点思维导图，包含连续时间和离散时间信号、 自变量的线性变换、指数和正弦信号等。

一、信号的表示方法

• 1.1 Continuous-Time and Discrete-Time Signals
  • Types of signals
    • Discrete-Time Signals
    • Continuous-Time Signals
  • Signal energy and power
    • Example:
    • 1)power
    • 2)energy
    • 3)average power
    • 4)energy
    • 5)power
  • Classification of signals by energy and power
    • finite-energy signal
    • finite-Power signal
    • Infinite-energy-and-power signal
• 1.2 Linear Transformation of the Independent Variable
  • Time transformation
    • Time Shift:左加右减
    • Time Reversal：
    • Time Scaling(only for continuous signal) :
      •  
    • General Linear Time Transform:
      • 将变换后的括号内的式子视为变量t
  • Periodic signals
  • Even and Odd Signals
    • Definition
      • even:
      • odd:
    • Even and Odd Parts of Signal
      • even:
      • odd:
      • relation:
• 1.3 Exponential & Sinusoidal Signals
  • Continuous-Time
    • Real Exponential
    • Periodic Complex Exponential
      • 基波周期
    • Sinusoidal Signals
    • Periodic CE vs S Signals
    • General CE vs variable S signals
      • • 
  • Discrete-Time
    • Real Exponential Signals
      • 始终为实数
    • CE vs S Signals
    • General CE vs variable S signals
      • • 
  • Periodicity of Discrete-Time CE and S Signals
• 1.4 Unit Impulse and Unit Step Functions
  • Discrete-Time UI and USS
    • Unit Impulse
    • Unit Step
    • relationship:
    • properties:
  • Dontinuous-Time UI and USS
    • unit step
    • unit pulse
    • relationship:
    • Properties:
• 1.5 Continuous-Time and Discrete-Time Systems
  • Continuous-Time and Discrete-Time Systems
    • CT:
    • DT:
  • Interconnection of Systems
    • Series Interconnection（级联）
    • Parallel Interconnection
    • Series-Parallel Interconnection
      • 
    • Feedback Interconnection
      • 
• 1.6 Classifications of Systems
  • 也许可以画个正方体，三个坐标轴分别代表过去现在将来
  • Memory
    • Memoryless system：输出只和现在的输入有关
    • Memory system：输出和过去、未来（也可以包含现在）的输入有关
  • Invertability
    • Invertible Systems：不同输入对应不同输出
    • Inverse system：
  • Causality
    • Causal Systems：输出和未来的输入无关
    • not Causal system：输出和未来的输入有关
  • Stability
    • Stable system：有界的输入（指x(t)）产生有界的输出（指y(t)）
      • 
  • Time-Invariant
    • Time-Invariant: 变量前无系数（System behave does not changes over time）
    • Time-Variant:变量前有系数
  • Linearity
    • Defn
      • Linearity = Addition + Homogeneity
        • 
    • Properties
      • Superposition
      • Zero input / output
      • Differential / Difference Property