Signals & Systems Questions and Answers – Signal Classification and Properties – 1

This set of Signals & Systems Multiple Choice Questions & Answers (MCQs) focuses on “Signal Classification and Properties – 1”.

1. Which of the following signals are monotonic in nature?
a) 1-exp(-t)
b) 1-exp(sin(t))
c) log(tan(t))
d) cos(t)
View Answer

Answer: a
Explanation: All of the other functions have a periodic element in them, which means the function attains the same value after a period of time, which should not occur for a monotonic function.

2. What is the period of the following signal, x(t) = sin(18*pi*t + 78 deg)?
a) 19
b) 29
c) 13
d) 49
View Answer

Answer: a
Explanation: The signal can be expressed as sin(wt + d), where the time period = 2*pi/w.
From the given equation, w = 18*pi. So, time period will be (2*pi)/(18*pi) = 1/9.

3. Which of the following signals is monotonic?
a) x(t) = t3 – 2t
b) x(t) = sin(t)
c) x(t) = sin22(t) + cos22(t) – 2t
d) x(t) = log(cos(t))
View Answer

Answer: c
Explanation: c) reduces to 1 – 2t, which is a strictly decreasing function.
advertisement

4. For the signal, x(t) = log(cos(a*pi*t+d)) for a = 50 Hz, what is the time period of the signal, if periodic?
a) 0.16s
b) 0.08s
c) 0.12s
d) 0.04s
View Answer

Answer: d
Explanation: Time period = 2*pi/(50)pi = 1/25 = 0.04s

5. What are the steady state values of the signals, 1-exp(-t), and 1-k*exp(-k*t)?
a) 1, k
b) 1, 1/k
c) k, k
d) 1, 1
View Answer

Answer: d
Explanation: Consider limit at t tending to infinity, we obtain 1 for both cases.
Free 30-Day Python Certification Bootcamp is Live. Join Now!

6. For a bounded function, is the integral of the function from -infinity to +infinity defined and finite?
a) Yes
b) Never
c) Not always
d) None of the mentioned
View Answer

Answer: c
Explanation: If the bounded function, is say y = 2, then the integral ceases to hold. Similarly, if it is just the block square function, it is finite. Hence, it depends upon the spread of the signal on either side. If the spread is finite, the integral will be finite.

7. For the signal x(t) = a – b*exp(-ct), what is the steady state value, and the initial value?
a) c, b
b) c, c-a
c) a, a-b
d) b, a-b
View Answer

Answer: c
Explanation: Put the limits as t tends to infinity and as t tends to zero.

8. For a double sided function, which is odd, what will be the integral of the function from -infinity to +infinity equal to?
a) Non-zero Finite
b) Zero
c) Infinite
d) None of the mentioned
View Answer

Answer: b
Explanation: For an odd function, f(-x) = -f(x), thus the integrals will cancel each other, giving zero.

9. Find where the signal x(t) = 1/(t2 – 3t + 2) finds its maximum value between (1.25, 1.75):
a) 1.40
b) 1.45
c) 1.55
d) 1.50
View Answer

Answer: d
Explanation: Differentiate the function for an optima, put it to zero, we will obtain t = 1.5 as the required instant.
advertisement

10. Is the signal x(t) = exp(-t)*sin(t) periodic in nature?
a) Yes
b) No
View Answer

Answer: b
Explanation: Though sin(t) is a periodic function, exp(-t) is not a periodic function, thus leading to non-periodicity.

Sanfoundry Global Education & Learning Series – Signals & Systems.

To practice all areas of Signals & Systems, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
I’m Manish - Founder and CTO at Sanfoundry. I’ve been working in tech for over 25 years, with deep focus on Linux kernel, SAN technologies, Advanced C, Full Stack and Scalable website designs.

You can connect with me on LinkedIn, watch my Youtube Masterclasses, or join my Telegram tech discussions.

If you’re in your 40s–60s and exploring new directions in your career, I also offer mentoring. Learn more here.