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

This is the Multiple 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

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

Continue Practice Exam Test Questions Part 4 of the Series

⇐ MCQ in Digital and Data Communication Networks Part 3 | ECE Board

Choose the letter of the best answer in each questions.

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

152. The circuit switch is a _______ switch.

a. See – through

b. Transparent

c. Vague

d. Opaque

153. A carrier recovery is needed with

a. FSK

b. BPSK

c. DPSK

d. QAM

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

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

156. Pulse – amplitude modulation signals are multiplexed by using

a. Subcarrier

b. Bandpass filters

c. A/D converters

d. FET switches

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

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

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

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

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

a. a telephone

b. teletype

c. telegraph

d. CW

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

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

a. baseband

b. broadband

c. ring

d. bus

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

165. Which of the following is not a LAN?

a. PBX system

b. Hospital system

c. Office building system

d. Cable TV system

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

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

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

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

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

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

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

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

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

175. T1 stands for

a. Transmission one

b. Telecommunication one

c. Telex one

d. Transmission line one

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

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

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

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

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

a. Data

b. Flow

c. Control

d. Bearer

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

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

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

184. The primary advantage of digital transmission

a. economical

b. reliability

c. noise immunity

d. efficiency

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

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

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

a. Frame time

b. Baud

c. Transmission time

d. Epoch

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

a. Shift register

b. XOR

c. 2 – to – 4 level converter

d. UART

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

190. Data communications refers to the transmission of

a. voice

b. video

c. computer data

d. all of the above

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

192. The basic modulator and demodulator circuits in PSK are

a. PLLs

b. Balanced modulators

c. Shift registers

d. Linear summers

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

194. Information capacity is convenient to express as

a. baud

b. bits

c. dot length

d. bits per second or bps

195. Which medium is the least susceptible to noise?

a. twin lead

b. fiber – optic cable

c. twisted pair

d. coax

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

197. The ISDN channel B designates _________.

a. Bearer

b. Data

c. Control

d. Flow

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

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

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

Questions and Answers in Digital and Data Communication Networks Series

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

Complete List of MCQ in Communications Engineering per topic