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 nonlin…(생략)

(a)