Problems On Signals & Systems

Today we are presenting previous year questions on signals & systems so this is useful for EC & EN 2nd year..

These problems are collected by BABITA RAWAT, studing in EC 2nd year.


Q1. Classify signals according to signal characteristics.

Q2. What do you understand by unit-step, unit ramp & unit impulse signal?

Q3. Differentiate b/w periodic & non-periodic signals.

Q4. Sketch the following signal
X (t) =B [u (t+2)-u (t-2)]

Q5. Show that the distinguishable range of digital frequency is of length 2π only.

Q6. With suitable examples, define the periodic & non-periodic signals.
Let x1(t) =sin (2πf1t)
& x2(t) =cos (8πf2t)
Be the two periodic signals, where f1 & f2 are two arbitrary constants. Determine the condition for which the signal
X (t) =x1(t) +x2(t)
Should also be a periodic signal?

Q7. Sketch the following signal
X (t) =A [u (t+a)-u (t-a)] for a>0
Also determine whether the given signal is a power signal or an energy signal.

Q8. Explain the continuous-time & discrete-signal unit-step functions.

Q9. Define a Random signal. In what terms, we analyze a Random signal?

Q10. Prove that a signal cannot be both an energy & power signal.

Q11. Show how that the impulse function can be defined as a sequence of:

(i) Triangular function?
(ii) Sampling function, where all operations on impulse function are viewed as operations on the sequence?

Q12. Let x1(t) & x2(t) be periodic signals with fundamental periods T1 & T2 respectively. Under what conditions is the sum?
X (t) =x1(t) +x2(t) periodic, & what is the fundamental period of x (t) if it is periodic.

Q13. Determine whether each of the following sequences are periodic or not. If
periodic, determine the fundamental period:

(i) X1(n)= sin (6πn/7)
(ii) X2(n)=sin(n/8)

Q14. Examine whether the following signal
X (n) =cos (n/10) cos (nπ/10) is periodic signal or not.

Q15. Determine the energy of the signal
X (t) =cos (10πt) u (t) x (t-2)


-Compiled by

BABITA RAWAT