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

(Last Updated On: April 8, 2020) This is the Multiples Choice Questions Part 3 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 3 of the Series

101. It is defined as knowledge or intelligence that is communicated between two or more points.

a. Carrier

b. Sideband

c. Information

Solution:

102. What is the category of data transmission if the binary pulse is maintained for the entire bit time?

b. Bipolar

c. Unipolar

Solution:

103. Which medium is the most widely used in LANs?

b. Fiber – optic cable

c. Twisted Pair

d. Coax

Solution:

104. These are used for transmission of PCM encoded time – division multiplexed digital signal.

a. I carriers

b. E carriers

c. A carriers

d. T carriers

Solution:

105. Which of the following is not a typical FDM application?

a. Telemetry

c. Telephone

d. Secure communications

Solution:

106. A LAN device that is used to interconnect two networks that use different protocols and formats.

a. Gateways

b. Routers

c. Bridges

d. Hubs

Solution:

107. A pulse modulation technique as the width of a constant amplitude pulse is varied proportional to the amplitude of the analog signal at the time the signal is sampled.

a. Pulse Width Modulation

b. Pulse Length Modulation

c. Pulse Duration Modulation

d. All of these

Solution:

108. The FDM telephone systems accommodate many channels by

a. Increasing the multiplexer size

b. Using many final carriers

c. Narrowing the bandwidth of each

d. Using multiple levels of multiplexing

Solution:

109. It is the transmittal of digitally modulated analog signals (carrier) between two or more points in a communications system.

a. Digital modulation

b. Digital transmission

c. Data communications

d. Pulse modulation

Solution:

110. Indicate which of the following systems is digital.

a. Pulse-position modulation

b. Pulse-code modulation

c. Pulse–width modulation

d. Pulse-frequency modulation

Solution:

111. Classification of protocol that interprets a frame of data as a group of successive bit combined into predetermined pattern of fixed length, usually 8 bits each.

a. Character-oriented protocols

b. Byte-oriented protocols

c. Bit-oriented protocols

d. Character and Byte-oriented protocols

Solution:

112. Dividing the data block by a constant produces a remainder that is used for error detection. It is called the

a. Vertical redundancy check

b. Horizontal redundancy check

c. Block check character

d. Cyclic redundancy check

Solution:

113. Which of the following is not a benefit of spread spectrum?

a. Jam – proof

b. Security

d. Noise proof

Solution:

114. Converting analog signals to digital is done by sampling and ___________.

a. Quantizing

b. Companding

c. Pre – emphasis

d. Mixing

Solution:

115. It is a process of converting an infinite number of possibilities to a finite number of conditions.

a. Sampling

b. Coding

c. Quantization

d. Aliasing

Solution:

116. In T1, it is equal to the reciprocal of the sample rate

a. Slot Time

b. Transmission time

c. Frame time

d. Bit rate

Solution:

117. What is the final output of a multiplexer?

a. Baseband

b. Composite baseband

c. Information

d. Composite carrier

Solution:

118. The baud rate

a. is always equal to the bit transfer rate

b. is equal to twice the bandwidth of an ideal channel

c. is not equal to the signaling rate

d. is equal to one – half the bandwidth of an ideal channel

Solution:

119. Bit errors in data transmission are usually caused by

a. equipment failures

b. typing mistakes

c. noise

d. poor S/N ratio at receiver

Solution:

120. A digital modulation technique which is a form of constant – amplitude angle modulation similar to standard frequency modulation except the modulating signal is binary signal that varies between two discreet voltage levels.

a. QAM

c. PSK

d. FSK

Solution:

121. Start and stop bits, respectively, are

a. Mark, space

b. Space, mark

c. Space, space

d. Mark, mark

Solution:

122. It is the processing of analog signals using digital methods and includes band limiting and signals with filters, amplitude equalization, and phase shifting

a. Digital communications

b. Digital Signal Processing

c. Data communications

d. Carrier recovery method

Solution:

123. It is a network access method used primarily with LANs configured in a ring topology using either baseband or broadband transmission formats

a. Ethernet

b. Token passing

c. Token ring

d. Token bus

Solution:

124. A small telephone switching system that can be used as a LAN is called

a. Ring

b. WAN

c. UART

d. PBX

Solution:

125. The most common method used for sampling voice signals in PCM systems

a. unnatural sampling

b. flat top sampling

c. natural sampling

d. free sampling

Solution:

126. In PCM, it converts the PAM sampled to parallel PCM codes

a. Analog-to-Digital converter

b. Digital-to-analog converter

c. Pre-emphasis circuit

d. Compander

Solution:

127. The OSI layer that provides the control functions necessary to establish, manage and terminated the connections as required to satisfy the user request.

a. Application layer

b. Network layer

c. Session layer

d. Physical layer

Solution:

128. In PAM demultiplexing, the receiver clock is derived from

b. a highly accurate internal oscillator

c. the PAM signal itself

d. the 60 Hertz power line

Solution:

129. It is also known as digital modulation

a. Digital transmission

b. Digital sampling

d. Data transmission

Solution:

130. Time – division multiplex

a. can be used with PCM only

b. combines five groups into supergroup

c. stacks 24 channels in adjacent frequency slots

d. interleaves pulses belonging to different transmissions

Solution:

131. It is a numerical indication of how efficiently a PCM code is utilized

a. Coding efficiency

b. Companding

c. Pre-emphasis

d. Dynamic Range

Solution:

132. Type of PCM which is designed to take advantage of the sample-to-sample redundancies in the typical speech waveform

a. Single – bit PCM code

b. Pulse Code Modulation

c. Differential PCM

d. Delta modulation

Solution:

133. The Basic Rate Interface (BRI) of ISDN has a total bit rate of _____.

a. 192 kbps

b. 148 kbps

c. 64 kbps

d. 1.544 Mbps

Solution:

134. A form of angle – modulated, constant amplitude digital modulation similar to conventional phase modulation except its input is binary digital signal and there are limited numbers of output phase possible.

b. PSK

c. FSK

d. QAM

Solution:

135. The main circuit in a PSN generator is ____.

a. XOR

b. Multiplexer

c. Shift register

d. Mixer

Solution:

136. The circuit that performs demultiplexing in an FDM system is _____.

a. Op – Amp

b. Bandpass filter

c. Discriminator

d. Subcarrier oscillator

Solution:

137. __________ defines how a user gets control of the channel so as to allow transmission.

a. channel access

b. collision detection

c. collision avoidance

d. carrier sense

Solution:

138. The fastest LAN topology is the

a. ring

b. bus

c. star

d. square

Solution:

139. It is a the symmetrical expectation of the bit error rate in the system

a. probability of errors

b. error detection

c. error control

d. bit error rate

Solution:

140. It is simply the data rate at which serial PCM bits are clocked out of the PCM encoder onto the transmission line.

a. line speed

b. baud rate

c. output rate

d. bit rate

Solution:

141. A quantizing is _______.

a. Multiplexer

b. Demultiplexer

c. A/D converter

d. D/A converter

Solution:

142. Refers to the rate of change of a signal on a transmission medium after encoding and modulation have occurred

a. baud rate

b. phase shift

c. bit rate

d. frequency deviation

Solution:

143. The magnitude difference between adjacent steps in quantization is called __________.

a. Quantum

b. Step size

c. Resolution

d. Any of these

Solution:

144. It is a set of rules implementing and governing an orderly exchange of data between layers of two devices, such as line control units and front – end processors.

b. Network Protocol

c. Point to Point Protocol

d. File Transfer Protocol

Solution:

145. A signaling system in which each letter of the alphabet is represented by a different symbol is not used because

a. it would be too difficult for an operator to memorize

b. it is redundant

c. noise would introduce too many errors

d. too many pulses per letter are required

Solution:

146. A modulation process that involves conversion of a waveform from analog to digital form by means of coding.

a. PDM

b. PCM

c. PLM

d. PAM

Solution:

147. What is the bandwidth required to transmit at a rate of 10 Mbps in the presence of a 28-bd S/N ratio?

a. 1.075 MHz

b. 10 MHz

c. 5 MHz

d. 10.5 MHz

Solution:

148. The slope of the analog signal is greater than the delta modulator can maintain

b. granular noise

d. peak limiting

Solution:

149. A scheme in which several channels are interleaved and then transmitted together is known as

a. Frequency division multiplex

b. Time division multiplex

c. a group

d. a supergroup

Solution:

150. The best frequency demodulator is the

a. PLL discriminator

b. Pulse-averaging discriminator

c. Foster-Seeley discriminator

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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