
Online Questions and Answers Topic Outline
- 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
MCQs in Digital and Data Communication Networks Series
Following is the list of multiple choice questions in this brand new series:
Continue Practice Exam Test Questions Part III 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
- d. Broadband
102. What is the category of data transmission if the binary pulse is maintained for the entire bit time?
- a. Return to zero
- b. Bipolar
- c. Unipolar
- d. Non – return to zero
103. Which medium is the most widely used in LANs?
- a. Twin Lead
- b. Fiber – optic cable
- c. Twisted Pair
- d. Coax
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
105. Which of the following is not a typical FDM application?
- a. Telemetry
- b. Stereo broadcasting
- c. Telephone
- d. Secure communications
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
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
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
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
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
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
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
113. Which of the following is not a benefit of spread spectrum?
- a. Jam – proof
- b. Security
- c. Immunity of fading
- d. Noise proof
114. Converting analog signals to digital is done by sampling and ___________.
- a. Quantizing
- b. Companding
- c. Pre – emphasis
- d. Mixing
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
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
117. What is the final output of a multiplexer?
- a. Baseband
- b. Composite baseband
- c. Information
- d. Composite carrier
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
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
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
- b. ASK
- c. PSK
- d. FSK
121. Start and stop bits, respectively, are
- a. Mark, space
- b. Space, mark
- c. Space, space
- d. Mark, mark
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
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
124. A small telephone switching system that can be used as a LAN is called
- a. Ring
- b. WAN
- c. UART
- d. PBX
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
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
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
128. In PAM demultiplexing, the receiver clock is derived from
- a. standard radio station WWV
- b. a highly accurate internal oscillator
- c. the PAM signal itself
- d. the 60 Hertz power line
129. It is also known as digital modulation
- a. Digital transmission
- b. Digital sampling
- c. Digital radio
- d. Data transmission
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
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
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
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
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.
- a. ASK
- b. PSK
- c. FSK
- d. QAM
135. The main circuit in a PSN generator is ____.
- a. XOR
- b. Multiplexer
- c. Shift register
- d. Mixer
136. The circuit that performs demultiplexing in an FDM system is _____.
- a. Op - Amp
- b. Bandpass filter
- c. Discriminator
- d. Subcarrier oscillator
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
138. The fastest LAN topology is the
- a. ring
- b. bus
- c. star
- d. square
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
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
141. A quantizing is _______.
- a. Multiplexer
- b. Demultiplexer
- c. A/D converter
- d. D/A converter
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
143. The magnitude difference between adjacent steps in quantization is called __________.
- a. Quantum
- b. Step size
- c. Resolution
- d. Any of these
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.
- a. Data Link Protocol
- b. Network Protocol
- c. Point to Point Protocol
- d. File Transfer Protocol
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
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
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
148. The slope of the analog signal is greater than the delta modulator can maintain
- a. overload distortion
- b. granular noise
- c. slope overload
- d. peak limiting
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
150. The best frequency demodulator is the
- a. PLL discriminator
- b. Pulse-averaging discriminator
- c. Foster-Seeley discriminator
- d. Radio detector
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