20 Communication Systems Interview Questions and Answers

In a technical interview for a position in communication systems, you may be asked a variety of questions about your experience and knowledge. It is important to be prepared to answer these questions confidently in order to demonstrate your qualifications for the role. In this article, we review some common questions you may encounter during your interview and provide tips on how to answer them.

Communication Systems Interview Questions and Answers

Here are 20 commonly asked Communication Systems interview questions and answers to prepare you for your interview:

1. What is communication systems?

Communication systems refers to the various types of systems that are used to facilitate communication between two or more parties. This can include everything from simple systems like email and instant messaging to more complex systems like video conferencing and VoIP.

2. Can you explain what a system is in the context of communications engineering?

A system is a collection of components that work together to achieve a common goal. In the context of communications engineering, a system is a collection of devices and software that work together to transmit information from one location to another.

3. What are some of the branches of communication systems?

The main branches of communication systems are wired and wireless communication systems.

4. What is the difference between analog and digital signals?

Analog signals are continuous, meaning that they can take on any value within a given range. Digital signals, on the other hand, are discrete, meaning that they can only take on a limited number of values.

5. What is modulation?

Modulation is the process of encoding information onto a carrier signal. This can be done in a number of ways, depending on the type of information being encoded and the type of signal being used. For example, amplitude modulation (AM) encodes information onto a carrier signal by varying the amplitude of the signal, while frequency modulation (FM) encodes information by varying the frequency of the signal.

6. What are some examples of modulated carrier waveforms?

Some examples of modulated carrier waveforms are amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM).

7. What do you understand by baseband transmission and broadband transmission?

Baseband transmission is a type of digital signal transmission where the signal is not modulated. This means that the signal is not changed in any way to carry information. The signal is instead sent as is, which can make it more susceptible to noise and interference. Broadband transmission is a type of digital signal transmission where the signal is modulated. This means that the signal is changed in some way to carry information. The signal is then sent as a series of pulses, which can make it less susceptible to noise and interference.

8. What is the difference between amplitude modulation and frequency modulation?

The main difference between amplitude modulation and frequency modulation is that, in amplitude modulation, the amplitude of the carrier signal is varied in accordance with the amplitude of the message signal, while in frequency modulation, the frequency of the carrier signal is varied in accordance with the amplitude of the message signal.

9. How can an FM signal be demodulated?

The most common way to demodulate an FM signal is to use a phase locked loop.

10. What is passband transmission?

Passband transmission is a type of digital transmission where the signal is first converted to an analog signal, which is then sent through a bandpass filter. The bandpass filter allows only certain frequencies to pass through, which are then converted back to a digital signal on the receiving end. This type of transmission is used in order to reduce noise and interference.

11. What’s the difference between cellular networks and mobile networks?

Cellular networks are made up of a series of interconnected cells, each of which is serviced by a separate antenna. Mobile networks, on the other hand, are made up of a single network of interconnected base stations.

12. Which type of wireless network has better coverage: 3G or 4G? Why?

4G wireless networks have better coverage than 3G wireless networks. This is because 4G networks use a different frequency than 3G networks, which allows for more data to be transmitted over a wider area. Additionally, 4G networks are constantly being upgraded, which means that they are able to provide even better coverage than 3G networks.

13. What is the main problem with communication over radio waves?

The main problem with communication over radio waves is that they are susceptible to interference. This can be caused by a number of factors, including natural phenomena like sunspots or electrical interference from other devices.

14. What is a BPSK signal?

BPSK stands for binary phase shift keying. It is a type of digital modulation where the phase of the carrier signal is shifted to represent either a 0 or a 1.

15. What is the importance of Nyquist sampling theorem?

The Nyquist sampling theorem is a fundamental result in the field of information theory, which states that a signal can be perfectly reconstructed from a sampled version of that signal if the sampling rate is greater than twice the bandwidth of the signal. This theorem is of paramount importance in the design of digital communication systems, as it provides a means of converting a continuous-time signal into a discrete-time signal without losing any information.

16. Can you give me some example applications of Fourier Transforms?

Fourier Transforms are used in a variety of applications, including signal processing, image processing, and data compression. In signal processing, Fourier Transforms can be used to filter out unwanted frequencies or to isolate specific frequencies of interest. In image processing, Fourier Transforms can be used to sharpen or blur images, or to remove noise. And in data compression, Fourier Transforms can be used to reduce the size of data files by identifying and removing redundant information.

17. What is Shannon-Hartley Theorem?

Shannon-Hartley theorem is a formula that is used to calculate the maximum amount of data that can be transmitted over a channel with a given bandwidth and noise level. This theorem is used in many different fields, including telecommunications and information theory.

18. What is channel capacity?

Channel capacity is the theoretical maximum amount of information that can be transmitted over a given channel in a given amount of time.

19. What is Doppler effect?

The Doppler effect is a change in frequency of a wave for an observer moving relative to the source of the wave. The effect is named after Austrian physicist Christian Doppler, who described it in 1842.

20. How does noise affect information transfer?

Noise can have a number of effects on information transfer, depending on the type of noise and the system in which it is present. In general, noise can introduce errors into a signal, making it more difficult for the receiver to correctly interpret the information. In some cases, noise can completely mask a signal, making it impossible to receive any information at all.