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§10. Chapter 10 The Z-Transform. Complex Frequency Domain (Z-Domain) Analysis of LTI System. ● Representation of Aperiodic Signals. ● Response of LTI System to Aperiodic Signals. §5. §5 Frequency Domain Analysis. 1. 2. 3. √. Frequency analysis. ﹡ Condition:. Frequency analysis.
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§10 Chapter 10 The Z-Transform Complex Frequency Domain (Z-Domain) Analysis of LTI System ●Representation of Aperiodic Signals ●Response of LTI System to Aperiodic Signals §5
§5 Frequency Domain Analysis 1 2 3 √ Frequency analysis ﹡ Condition: Frequency analysis ﹡ Problems: 10.0 Introduction
represent represent √ ﹡Cause: Basic signal: ﹡Measure: Basic signal:
we have Under Condition 反 ① ② 正 10.1 The Z-Transform Pair A. The Transform Pair z-plane Integral line
B. Understanding of The Transform Pairs ﹡Inverse Transform
Frequency Frequency
﹡ Similarity : ﹡ Similarity : ﹡The Transform
generally Integral line ROC , :基本信号 点: C. The Convergence Region of the Z-Transform : ROC
if ROC Let ROC D. Relations Between Z-Transform and Discrete-Time Fourier Transform Z-Transform on Unit Circle =Discrete-Time Fourier Transform
Condition=ROC ① if , Unit Circle ROC ROC 10.2 The Region of Convergence of The Z-Transform 10.2.1 The ROC. <Examples 10.1>
Unit Circle ROC ② if , Unit Circle 一般:右边信号 收敛域向外
Unit Circle ROC ① if , Unit Circle < Examples10.2>
then the Unit Circle ROC ② if , Unit Circle 一般:左边信号 收敛域向内
ROC for <10.1> <10.2> Integral Left-sided Right-sided ROC for Integral <10.1+10.2>
A. ROC : B. Poles ROC 10.2.3. General Rule for ROC 右边信号 双边信号 左边信号
: ROC C. ROC 双边信号 环形收敛域 或无收敛域
环形收敛域 无收敛域 双边信号 双边信号 <Example 10.7>
possibly except ROC: entire Z-plane, Poles at Pole at D. is finite duration “环形” “向内” “向外”
pole zero <Example 10.6>
收敛域向外 右边信号 E.
收敛域向内 左边信号 F.
ROC: Bounded by poles ﹡ ﹡ G. Rational ﹡Two-sided signal ﹡left-sided signal ﹡right-sided signal
zero pole 零点距离积 极点距离积 零点相位和 极点相位和 10.4 Geometric Evaluation of The Fourier Transform From The Zero-Pole Plot 10.4.1 Geometric Evaluation of Z-Transform A. The Method
Let if Unit Circle ROC, 10.4.2 Geometric Evaluation of Fourier Transform A. The Method as above, B. Example
10.5.1 Linearity 10.5.2 Time shifting shift ( 可能加入或去掉) 10.5 Properties of Z-Transform
<Proof> <Example>
内收 外扩 or Scaling 平移 10.5.3 Scaling in the Z-Domain <Proof>
1/R 10.5.4 Time Reversal <Proof>
Where integer ,if n is a multiple of k , else k=3 -4 -3 -2 -1 0 1 2 3 4 -4k -3k -2k -k 0 k 2k 3k 4k 补零 (时域扩展) 10.5.5 Time Expansion
For real signal : 10.5.6 Conjugation
10.5.7 The Convolution Property 10.5.8 Differentiation in Z- Domain
Differentiation Differentiation,Linear <Example> Important : useful in Inverse Z-Transform
Linearity, Time-scaling <Example>
For causal , 10.5.9 The Initial-value Theorem (检验变换的正确性) ,we have 10.5.10 Table 10.1 include all properties 10.6 Some Common Z-Transform Pairs Table 10.2
① Contour Integral 围线积分 ROC for any kind of ② Partial-Fraction Expansion Integral line: 部分分式展开 for rational 10.3 Inverse Z-Transform
A. Partial-Fraction Expansion for Rational 1. Basic Z-Transform Pairs (10.5.8 example)
一阶极点 二阶极点 一阶极点 ① ② Get by Formula in Appendix (Partial-Fraction Expansion) ③ ROC ④ 2. Idea
B. Examples ① ②
左 for ROC: ② ③ 右 左 for ROC: 右 for ROC:
10.7 Analysis and Configuration of LTI systems using Z-Transform 10.7.1 System Function of LTI System : A. Response of LTI System to ,where System Function System Function or Transfer Function
幅频特性(给定 ) 相频特性(给定 ) B. Explanation of (类似于 ) 对各衰减因子各频率的衰减复正弦信号的幅度调整和相位调整作用 其中: or 函数集 的选择
<Example> Integral Line
C. The Method to Obtain 1. From : 2. From the Linear-Coefficient Different Equation of LTI System , Linearity, Time-Shifting
Coefficient of right-side of Equ. Coefficient of left-side of Equ. <Example>
10.7.2 System Performance vs. A. Causality vs. 1. exterior outside of a circle ① Causality ROC: 2. including Cross outer most pole Causality 1. exterior outside of a circle ROC: ② 2. Including Rational ① ②
B. Stability vs. Stability ROC Fourier Transform ROC Stable Unstable Unstable
<Example> Unstable, causal Stable, noncausal Unstable, noncausal
C. Stable & Causal System ~ Causality All poles lies inside unit circle Exterior to the circle Acrossing outer most pole Rational Stability
10.7.3 Z-Domain Analysis of LTI System 1. Idea : Basic relation between input and output : Relation between any input and output ①信号分解 ②已知输入输出 ③响应合成