logo
  • Home
  • About
  • Training
  • Programming
  • CS
  • IT
  • IS
  • ECE
  • EEE
  • EE
  • Civil
  • Mechanical
  • Chemical
  • Metallurgy
  • Instrumentation
  • Aeronautical
  • Aerospace
  • Biotechnology
  • Agriculture
  • MCA
  • BCA
  • Internship
  • Contact

Digital Communications Multiple Choice Questions | MCQs | Quiz

Digital Communication Interview Questions and Answers
Pratice Digital Communication questions and answers for interviews, campus placements, online tests, aptitude tests, quizzes and competitive exams.

Get Started

•   Signal Processing
•   Signal Classification
•   Spectral Density
•   Random Signals
•   Baseband System
•   Noise - 1
•   Noise - 2
•   Digital Communication
•   DC System - 1
•   DC System - 2
•   Process Types
•   Signals
•   Analog Information
•   Corruption Sources
•   Pulse Code Modulation
•   Non Uniform Quantization
•   Baseband Transmission - 1
•   Baseband Transmission - 2
•   Correlative Coding
•   Sampling & Quantization - 1
•   Sampling & Quantization - 2
•   Signals & Noises
•   Intersymbol Interference - 1
•   Intersymbol Interference - 2
•   Equalization
•   Non Coherent Detection
•   Bandpass Techniques
•   Coherent Detection
•   M-ary Signalling
•   Link Budget Analysis
•   Link Budget Error Control
•   Noise Parameters
•   Waveform Coding
•   Structured Sequence
•   Error Detection
•   Linear Block Codes
•   Convolution Encoding
•   Reed Solomon Code
•   Concatenated Codes
•   Shannon Hartley Theorem
•   Bandwidth Modulation
•   Communication Resources
•   Trellis Coded Modulation
•   PAM, PWM & TDM
•   M-ary Modulation
•   Modulation & Multiplexing
•   Modulation & Entropy
•   Modulation Techniques
•   Network Synchronization
•   Receiver Synchronization
•   Spread Spectrum & TDMA
•   Access Algorithm
•   INTELSAT
•   TDM & FDM
•   TDM vs FDM
•   Spread Spectrum & CDMA
•   Pseudo Noise Sequence
•   Frequency Hopping
•   Acquisition & Tracking
•   Cellular Systems
•   Cipher Systems Secrecy
•   Stream Encryption
•   Spread Spectrum
•   Public Key Cryptosystems1
•   Public Key Cryptosystems2
•   Pretty Good Privacy
•   Mobile Radio Propagation
•   Signal Time Spreading
•   Rake Receivers
•   Decision Theory Effects
•   Abstraction & Layering
•   Protocols
•   Random Processes
•   ISDN & Interface
•   Error Detection - 1
•   Error Detection - 2
•   Codes & Coding Technique
•   Interpolation
•   Information & Coding
•   Quantization - 1
•   Quantization - 2

Best Reference Books

Digital Communication Books
« Prev Page
Next Page »

Digital Communications Questions and Answers – Coherent Detection

Posted on November 3, 2015 by Manish

This set of Digital Communications Multiple Choice Questions & Answers (MCQs) focuses on “Coherent detection”.

1. The correlating detector is also known as
a) Maximum likelihood detector
b) Minimum likelihood detector
c) Maximum & Minimum likelihood detector
d) None of the mentioned
View Answer

Answer: a
Explanation: Coherent detector considers phase as the most important parameter. This coherent detector is also known as maximum likelihood detector.

2. The minimum nyquist sampling rate is given as, fs =
a) 1/T
b) T
c) 2/T
d) 2T
View Answer

Answer: a
Explanation: The input signal comprises of a prototype signal plus noise and the bandwidth is 1/2T where T is the symbol time and minimum nyquist sampling rate can be given as 2W or 1/T.

3. Phase-locked loop circuitry is used for
a) Carrier wave recovery
b) Phase estimation
c) Carrier wave recovery & Phase estimation
d) None of the mentioned
View Answer

Answer: c
Explanation: The phase locked loop circuitry locks on the arriving carrier wave and estimates it phase.

4. In differential PSK the date is
a) Encoded differentially
b) Decoded differentially
c) Encoded & Decoded differentially
d) None of the mentioned
View Answer

Answer: a
Explanation: In this method , the data is encode deferentially that is the presence of binary zero or one is manifested by symbol’s similarity or difference when compared to that of the previous symbol.

5. Envelope detector consists of
a) Rectifier and high pass filter
b) Rectifier and low pass filter
c) Amplifier and low pass filter
d) Amplifier and high pass filter
View Answer

Answer: b
Explanation: An envelope detector consists of a rectifier and a low pass filter. The detectors are matched to the envelopes and not to the signal themselves.

6. The minimum required spacing is the difference between the
a) Center of the spectral main lobe and first zero crossing
b) First and second zero crossing
c) First and last zero crossing
d) None of the mentioned
View Answer

Answer: a
Explanation: The frequency difference between the center of the spectral main lobe and the first zero crossing is called as the minimum required spacing in non coherent detection.

7. The minimum tone separation corresponds to
a) T
b) 1/T
c) 2T
d) T/2
View Answer

Answer: b
Explanation: In non coherent detection the minimum tone separation corresponds to 1/T.

8. Matched filter is used for
a) Coherent detection
b) Non coherent detection
c) Coherent & Non coherent detection
d) None of the mentioned
View Answer

Answer: a
Explanation: Matched filter is used for coherent detection. It cannot be used for non coherent detection because matched filter output is a function of unknown angle α.

9. In differential encoding the _________ different between two wave forms is measured.
a) Magnitude
b) Frequency
c) Phase
d) Time period
View Answer

Answer: c
Explanation: In differential encoding the phase of the present signal waveform is compared with the phase of the previous signal.

10. The error probability of DPSK is ________ worse than PSK.
a) Twice
b) 3 db
c) Twice (3db)
d) None of the mentioned
View Answer

Answer: c
Explanation: DPSK has twice as much as noise than in PSK. The error probability in DPSK is twice (3db) worse than PSK.

Sanfoundry Global Education & Learning Series – Digital Communications.

To practice all areas of Digital Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.

« Prev Page - Digital Communications Questions and Answers – Digital Bandpass Modulation Techniques
» Next Page - Digital Communications Questions and Answers – M-ary Signalling and Performance
« Digital Communications Questions and Answers – Digital Bandpass Modulation Techniques
Digital Communications Questions and Answers – M-ary Signalling and Performance »

Deep Dive @ Sanfoundry:

  1. Electric Circuits Questions and Answers
  2. Electronic Devices and Circuits Questions and Answers
  3. Control Systems Questions and Answers
  4. Network Theory Questions and Answers
  5. Digital Circuits Questions and Answers
  6. Linear Integrated Circuits Questions and Answers
  7. Digital Image Processing Questions and Answers
  8. Optical Communications Questions and Answers
  9. Digital Signal Processing Questions and Answers
  10. Digital Communication Questions and Answers
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below:
LinkedIn | Facebook | Twitter | Google+

Best Careers

Developer Tracks
SAN Developer
Linux Kernel Developer
Linux Driver Developer
Linux Network Developer

Live Training Photos
Mentoring
Software Productivity
GDB Assignment
Sanfoundry is No. 1 choice for Deep Hands-ON Trainings in SAN, Linux & C, Kernel Programming. Our Founder has trained employees of almost all Top Companies in India such as VMware, Citrix, Oracle, Motorola, Ericsson, Aricent, HP, Intuit, Microsoft, Cisco, SAP Labs, Siemens, Symantec, Redhat, Chelsio, Cavium, ST-Micro, Samsung, LG-Soft, Wipro, TCS, HCL, IBM, Accenture, HSBC, Mphasis, Tata-Elxsi, Tata VSNL, Mindtree, Cognizant and Startups.

Best Trainings

SAN I - Technology
SAN II - Admin
Linux Fundamentals
Advanced C Training
Linux-C Debugging
System Programming
Network Programming
Linux Threads
Kernel Programming
Kernel Debugging
Linux Device Drivers

Best Reference Books

Computer Science Books
Algorithm & Programming Books
Electronics Engineering Books
Electrical Engineering Books
Chemical Engineering Books
Civil Engineering Books
Mechanical Engineering Books
Industrial Engineering Books
Instrumentation Engg Books
Metallurgical Engineering Books
All Stream Best Books

Questions and Answers

1000 C Questions & Answers
1000 C++ Questions & Answers
1000 C# Questions & Answers
1000 Java Questions & Answers
1000 Linux Questions & Answers
1000 Python Questions
1000 PHP Questions & Answers
1000 Hadoop Questions
Cloud Computing Questions
Computer Science Questions
All Stream Questions & Answers

India Internships

Computer Science Internships
Instrumentation Internships
Electronics Internships
Electrical Internships
Mechanical Internships
Industrial Internships
Systems Internships
Chemical Internships
Civil Internships
IT Internships
All Stream Internships

About Sanfoundry

About Us
Copyright
TOS & Privacy
Jobs
Bangalore Training
Online Training
SAN Training
Developers Track
Mentoring Sessions
Contact Us
Sitemap
© 2011 Sanfoundry