신호와 시스템 1장 솔루션.doc

Solutions to Exercises of Chapter 1 Exercises with Solutions Exercise 1.1 Write the following complex signals in polar form, i.e., in the form for continuous-time signals, for discrete-time signals. (a) Answer: (b) Answer: Exercise 1.2 Determine if the following systems are: 1. Memoryless, 2. Time-invariant, 3. Linear, 4. Causal, 5. BIBO Stable. Justify your answers. (a) Answer: 1. Memoryless No. For example, the output depends on a future value of the input. 2. Time-invariant No. 3. Linear Yes. Let . Then, the output of the system with is given by: 4. Causal No. For example, the output depends on a future value of the input. 5. Stable Yes. . (b) Answer: 1. Memoryless No. The system has memory since at time , it uses the past value of the input . 2. Time-invariant Yes. 3. Linear No. The system is nonlinear since it does not have the superposition property: 4. Causal Yes. The system is causal as the output is a function of the past and current val…
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