Anna University Regulation 2013 Electronics and Communication Engineering (ECE) EC6303 SS 2marks & 16marks for all 5 units are provided below. Download link for ECE 3rd SEM EC6303 Signals & Systems Short answers, Question Bank are listed down for students to make perfect utilization and score maximum marks with our study materials.

UNIT I CLASSIFICATION OF SIGNALS AND SYSTEMS
1. Define Signal.
Signal is a physical quantity that varies with respect to time, space or any other independent variable.(Or) It is a mathematical representation of the system Eg y(t) = t. and x(t)= sin t.
2. Define system.
A set of components that are connected together to perform the particular task.
3. What are the major classifications of the signal?
(i) Discrete time signal (ii) Continuous time signal
4. Define discrete time signals and classify them.
Discrete time signals are defined only at discrete times, and for these signals, the independent variable takes on only a discrete set of values. Classification of discrete time signal:
1. Periodic and A periodic signal 2. Even and Odd signal
5. Define continuous time signals and classify them.
Continuous time signals are defined for a continuous of values of the independent variable. In the case of continuous time signals the independent variable is continuous.
For example:
(i) A speech signal as a function of time (ii) Atmospheric pressure as a function of altitude
Classification of continuous time signal:
(i) Periodic and A periodic signal (ii) Even and Odd signal
6. Define discrete time unit step &unit impulse.(APRIL/MAY 2011) .(NOV/DEC-2014)
Discrete time Unit impulse is defined as
δ [n]= {0, n 0
{1, n=0
Unit impulse is also known as unit sample.
Discrete time unit step signal is defined by U[n]={0,n=0 {1,n>= 0
7. Define continuous time unit step and unit impulse.
Continuous time unit impulse is defined as δ (t)={1, t=0 {0, t 0
Continuous time Unit step signal is defined as U(t)={0, t<0 {1, t 0
8. Define unit ramp signal. (APRIL/MAY 2011)
Continuous time unit ramp function is defined by r(t)={0,t<0
{t, t 0
A ramp signal starts at t=0 and increases linearly with time‘t’.
9. Define periodic signal. and nonperiodic signal.
A signal is said to be periodic, if it exhibits periodicity.i.e., X(t +T)=x(t), for all values of t. Periodic signal has the property that it is unchanged by a time shift of T. A signal that does not satisfy the above periodicity property is called an aperiodic signal.
10. Define even and odd signal ? (MAY/JUNE 2010)
¾ A discrete time signal is said to be even when, x[-n]=x[n].The continuous time signal is said to be even when, x(-t)= x(t)
For example, Cosωn is an even signal.
¾ The discrete time signal is said to be odd when x[- n]= -x[n].The continuous time signal is said to be odd when x(-t)= -x(t)
Odd signals are also known as non symmetrical signal. Sine wave signal is an odd signal.

11. Define Energy and power signal. (APRIL/MAY 2011 &15)
¾ A signal is said to be energy signal if it have finite energy and zero power.
¾ A signal is said to be power signal if it have infinite energy and finite power.
¾ If the above two conditions are not satisfied then the signal is said to be neither energy nor power signal
12. Define unit pulse function.
Unit pulse function (t) is obtained from unit step signals u(t)=u(t+1/2)- u(t-1/2)
The signals u(t+1/2) and u(t-1/2) are the unit step signals shifted by 1/2units in the time axis towards the left and right ,respectively.
13. Define continuous time complex exponential signal.
The continuous time complex exponential signal is of the form x(t)=Ceat where c and a are complex numbers.
14. What is continuous time real exponential signal.
Continuous time real exponential signal is defined by x(t)=Ceat Where c and a are complex numbers. If c and a are real ,then it is called as real exponential.
15. What is continuous time growing exponential signal?
Continuous time growing exponential signal is defined as x(t)=Ceat,Where c and a are complex numbers. If a is positive,as t increases , then x(t) is a growing exponential.
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