Download Aptitude Crack
img not found img not found

Signals and Systems

Q1:

Which one is a linear system?

A y[n] = x[n] x x[n - 1]

B y[n] = x[n] + x[n - 10]

C y[n] = x2[n]

D (a) and (c)

ANS:B - y[n] = x[n] + x[n - 10]

For linearity y1[n] = x1[n] + x2[n - 10] ...(1) y2 = x2[n] + x2[n - 10] ...(2) y1[n] = x1[n] + x2[n] + x2[n - 10] + x2[n - 10] ...(3) Now find y1[n] + y2[n] Corresponding to x1[n] + x2[n] It is same as equation (3) hence linear. But in part (c) y[n] = x2[n] ⇒ y1[n] = x21[n], y2[n] = x22[n]⇒ y1[n] + y2[n] = x22[n]...3 But y1[n] + y2[n] Corresponing x1[n] + x2[n] is y1[n] + y2[n] = {x1[n] + x2[n]}2 = x12[n] + x22[n] + 2x1[n] x2[n]....4 Equations (3) and (4) are not same hence not linear.



img not found
img

For help Students Orientation
Mcqs Questions

One stop destination for examination, preparation, recruitment, and more. Specially designed online test to solve all your preparation worries. Go wherever you want to and practice whenever you want, using the online test platform.