# MCQ in Digital and Data Communication Networks Part 4 | ECE Board

(Last Updated On: April 10, 2020) This is the Multiples Choice Questions Part 4 of the Series in Digital and Data Communication Networks as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

#### MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQs in Bit and and Binary Transmission
• MCQs in Signaling Rate
• MCQs in Error Probability, Digital Filtering, Switching, Packet Circuit, Vertical Circuit
• MCQs in Open systems Interconnection
• MCQs in Multiplying, Modulation and Synchronization
• MCQs in Pulse Code Modulation, Companding, Encoding, Bandwidth and Signal to Noise Ratio
• MCQs in Delta Modulation, Slope Overload, Adaptive Delta Modulation, Codes and Protocol
• MCQs in Error Detection and Correction, Digital Carrier systems
• MCQs in Frequency Shift Keying, Phase Shift Keying, Differential Phase Shift keying
• MCQs in DC nature of data transmission, loops, Neutral and Polar
• MCQs in Binary transmission and the concept of time
• MCQs in Asynchronous and Synchronous, timing, Distortion, Bits, band, WPM
• MCQs in Data Interface standards, Data input/output devices
• MCQs in Digital Transmission on analog channel, Modulation-demodulation schemes parameters
• MCQs in Circuit conditioning, Modem Applications
• MCQs in Serial and Parallel Transmission

#### Continue Practice Exam Test Questions Part 4 of the Series

151. What property distinguishes digital radio systems from conventional analog communications system?

a. the type of carrier used in the transmission of data

b. the nature of the modulating signal

c. the type of modulation of data to be used

d. the nature of the transmitter and receiver to be used

View Answer:

Answer: Option B

Solution:

152. The circuit switch is a _______ switch.

a. See – through

b. Transparent

c. Vague

d. Opaque

View Answer:

Answer: Option B

Solution:

153. A carrier recovery is needed with

a. FSK

b. BPSK

c. DPSK

d. QAM

View Answer:

Answer: Option C

Solution:

154. The Hartley – Shannon theorem sets a limit on the

a. highest frequency that may be sent over a given channel

b. maximum capacity of a channel with a given noise level

c. maximum number of coding levels in a channel with a given noise level

d. maximum number of quantizing levels in a channel of a given bandwidth

View Answer:

Answer: Option B

Solution:

155. The phase relationship between signaling elements for BPSK is the optimum signaling format and occurs only when two binary signal levels are allowed and when one signal is the exact negative of the other.

a. Antipodal signaling

b. Carrier recovery

c. Squaring loop

d. Phase referencing

View Answer:

Answer: Option A

Solution:

156. Pulse – amplitude modulation signals are multiplexed by using

a. Subcarrier

b. Bandpass filters

c. A/D converters

d. FET switches

View Answer:

Answer: Option D

Solution:

157. It is the ratio of the transmission bit rate to the minimum bandwidth required for a particular modulation scheme.

a. Bandwidth efficiency

b. Spectral efficiency

c. Information density

d. All of these

View Answer:

Answer: Option D

Solution:

158. Ethernet is baseband transmission system designed by _____.

a. Thomas Murray and Robert Metcalfe

b. David Boggs and Thomas Murray

c. Thomas Murray and Emile Baudot

d. Robert Metcalfe and David Boggs

View Answer:

Answer: Option D

Solution:

159. It is a system where the digital signals are placed directly on the coaxial cable.

a. Broadband

b. Baseband

c. CSMA/CD

d. Token ring

View Answer:

Answer: Option B

Solution:

160. A basic group B

a. Occupies the frequency range from 60 to 108 kHz

b. Consists of erect channels only

c. Is formed at the group translating equipment

d. Consists of 5 supergroups

View Answer:

Answer: Option A

Solution:

161. Which of the following is not primarily type of data communications?

a. a telephone

b. teletype

c. telegraph

d. CW

View Answer:

Answer: Option A

Solution:

162. Packets which is self – contained and travels through the network independent of other packets of the same message by whatever means available.

a. Packet

b. Frame

c. Datagram

d. Data

View Answer:

Answer: Option C

Solution:

163. Transmitting the data signal directly over the medium is referred to as

a. baseband

b. broadband

c. ring

d. bus

View Answer:

Answer: Option A

Solution:

164. The main reason that serial transmission is preferred to parallel transmission is that?

a. serial is faster

b. serial requires only a single channel

c. serial requires multiple channels

d. parallel is too expensive

View Answer:

Answer: Option D

Solution:

165. Which of the following is not a LAN?

a. PBX system

b. Hospital system

c. Office building system

d. Cable TV system

View Answer:

Answer: Option D

Solution:

166. A modulation technique where data rates in excess of 56 kbps can be achieved over telephone circuits

a. ASK

b. Trellis Code Modulation

c. GSK

d. Any of these

View Answer:

Answer: Option B

Solution:

167. It is how the primary designates the secondary as the designation of recipient of data.

a. Line turnaround

b. Selection

c. Line control

d. Control Protocol

View Answer:

Answer: Option B

Solution:

168. It is the process of compressing and expanding and is a means of improving the dynamic range of communications system.

a. Pre-emphasis

b. Filtering

c. De-emphasis

d. Companding

View Answer:

Answer: Option D

Solution:

169. The supergroup pilot is

a. applied to each multiplexing bay

b. used to regulate the gain of individual repeaters

c. applied at each adjustable equalizer

d. fed in at a GTE

View Answer:

Answer: Option D

Solution:

170. The time it takes to transmit one TDM frame is called _________.

a. Slot time

b. Frame time

c. Transmission time

d. Any of these

View Answer:

Answer: Option B

Solution:

171. It is the thermal noise power normalized to 1-Hz bandwidth

a. power density ratio

b. thermal noise

c. noise power density

d. ambient temperature noise

View Answer:

Answer: Option C

Solution:

172. It is the procedure used to decide which device has the permission to transmit at any given time

a. Flow control

b. Sequence control

c. Line control

d. Framing

View Answer:

Answer: Option C

Solution:

173. Any rounded – off errors in the transmitted signal are reproduced when the code is converted back to analog in the receiver.

a. Aperture error

b. Quantization error

c. Aperture distortion

d. Slope overload

View Answer:

Answer: Option B

Solution:

174. The biggest disadvantage of PCM is

a. its inability to handle analog signals

b. the high error rate which is quantizing noise introduces

c. its incompatibility with TDM

d. the large bandwidths that are required for it

View Answer:

Answer: Option D

Solution:

175. T1 stands for

a. Transmission one

b. Telecommunication one

c. Telex one

d. Transmission line one

View Answer:

Answer: Option A

Solution:

176. Involves compression in the transmitter after the input sample has been converted to a linear PCM code and then expansion in the receiver prior to PCM coding.

a. analog companding

b. A – law companding

c. Digital companding

d. U – law companding

View Answer:

Answer: Option C

Solution:

177. Mark and space refer respectively to

a. dot and dash

b. message and interval

c. binary 1 and binary 0

d. on and off

View Answer:

Answer: Option C

Solution:

178. Variation of biphase that is used for encoding SMPTE time code data and for recording on video tapes

a. Biphase – M

b. B8Z

c. Manchester

d. UPNRZ

View Answer:

Answer: Option A

Solution:

179. Pulse width modulation may be generated

a. by differentiating pulse position modulation

b. with a monostable multivibrator

c. by integrating the signal

d. with a free running multivibrator

View Answer:

Answer: Option B

Solution:

180. The ISDN channel D designates _____ which contains control information.

a. Data

b. Flow

c. Control

d. Bearer

View Answer:

Answer: Option A

Solution:

181. A transmission of binary data which involves the transmission of two non – zero voltage level

a. Unipolar

b. Polar

c. Bipolar

d. Non – return to zero

View Answer:

Answer: Option C

Solution:

182. Switching systems

a. improve the efficiency of data transfer

b. are not used in data systems

c. require additional lines

d. are limited to small data networks

View Answer:

Answer: Option A

Solution:

183. It involves converting standard logic levels to a form more suitable to telephone transmission lines

a. Transmission line encoding

b. Physical line encoding

c. Digital line encoding

d. Multiplexing

View Answer:

Answer: Option C

Solution:

184. The primary advantage of digital transmission

a. economical

b. reliability

c. noise immunity

d. efficiency

View Answer:

Answer: Option C

Solution:

185. Part of the PCM system that prevents aliasing or foldover distortion

a. Bandpass filter

b. Anti – foldover distortion

c. Anti – aliasing

d. Any of these

View Answer:

Answer: Option D

Solution:

186. It is defined as the process of transforming messages or signals in accordance with a definite set of rules.

a. Quantizing

b. Sampling

c. Coding

d. Decoding

View Answer:

Answer: Option C

Solution:

187. The PCM code for each channel occupies a fixed time slot called

a. Frame time

b. Baud

c. Transmission time

d. Epoch

View Answer:

Answer: Option D

Solution:

188. The building block of a parity or BCC generator is _________.

a. Shift register

b. XOR

c. 2 – to – 4 level converter

d. UART

View Answer:

Answer: Option B

Solution:

189. An IC that contains A/D and D/A converters, companders, and parallel-to-serial converters is called a

a. Codec

b. Data converter

c. Multiplexer

d. Modem

View Answer:

Answer: Option A

Solution:

190. Data communications refers to the transmission of

a. voice

b. video

c. computer data

d. all of the above

View Answer:

Answer: Option C

Solution:

191. The number of amplitude, frequency, or phase changes that take place per second is known as the

a. data rate in bits per second

b. frequency of operation

c. speed limit

d. baud rate

View Answer:

Answer: Option D

Solution:

192. The basic modulator and demodulator circuits in PSK are

a. PLLs

b. Balanced modulators

c. Shift registers

d. Linear summers

View Answer:

Answer: Option B

Solution:

193. What is the result if the input of ADC is changing while performing conversion?

a. Aperture error

b. Overload distortion

c. Aliasing

d. Aperture distortion

View Answer:

Answer: Option D

Solution:

194. Information capacity is convenient to express as

a. baud

b. bits

c. dot length

d. bits per second or bps

View Answer:

Answer: Option D

Solution:

195. Which medium is the least susceptible to noise?

a. twin lead

b. fiber – optic cable

c. twisted pair

d. coax

View Answer:

Answer: Option B

Solution:

196. The RS – 232 interface

a. interconnects data sets and the transmission circuits

b. uses several different connectors

c. permits custom wiring of signal lines to the connector pins as desired

d. all of the above

View Answer:

Answer: Option A

Solution:

197. The ISDN channel B designates _________.

a. Bearer

b. Data

c. Control

d. Flow

View Answer:

Answer: Option A

Solution:

198. Data transmission of the character at a time with start and stop bits is known as what type of transmission?

a. asynchronous

b. serial

c. synchronous

d. parallel

View Answer:

Answer: Option A

Solution:

199. Sampling technique that when the tops of the sample pulses retain their natural shape during the sample interval

a. unnatural sampling

b. flat top sampling

c. natural sampling

d. free sampling

View Answer:

Answer: Option C

Solution:

200. A modem converts

a. Analog signals to digital

b. Digital signals to analog

c. Digital signals to analog and vice-versa

d. None of these

View Answer:

Answer: Option C

Solution:

#### Questions and Answers in Digital and Data Communication Networks Series

Following is the list of multiple choice questions in this brand new series:

Digital and Data Communication Networks MCQs
PART 1: MCQ from Number 1 – 50                        Answer key: PART 1
PART 2: MCQ from Number 51 – 100                   Answer key: PART 2
PART 3: MCQ from Number 101 – 150                 Answer key: PART 3
PART 4: MCQ from Number 151 – 200                 Answer key: PART 4
PART 5: MCQ from Number 201 – 250                 Answer key: PART 5
PART 6: MCQ from Number 251 – 300                 Answer key: PART 6
PART 7: MCQ from Number 301 – 350                 Answer key: PART 7

### Complete List of MCQ in Communications Engineering per topic

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