MCQ in Digital and Data Communication Networks Part 5 | ECE Board

This is the Multiple Choice Questions Part 5 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 5 of the Series

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

Choose the letter of the best answer in each questions.

201. It is a large scale integration chip designed for use in telecommunication industry for private branch exchanges, central office switches, digital handsets and digital echo suppressors.

a. Vocoder

b. Modem

c. Codec

d. Muldem

202. What is the type of mastergroup used for low – capacity microwave systems?

a. A600

b. U600

c. L600

d. L400

203. An FDM hierarchy which is formed by frequency – division multiplexing five groups containing 12 channels each for a combined bandwidth of 240 kHz.

a. Supergroup

b. Group

c. Mastergroup

d. Jumbogroup

204. The result whenever the sampling rate is less than twice the highest audio frequency

a. peak limiting

b. overload distortion

c. alias

d. quantizing noise

205. The most critical and difficult part of receiving a direct – sequence spread spectrum signal is

a. Frequency synthesis

b. Synchronism

c. PSN code generation

d. Carrier recovery

206. An FDM hierarchy which is formed by frequency – division multiplexing 10 super groups together for a combined capacity of 600 voice band message channels

a. Supergroup

b. Group

c. Mastergroup

d. Jumbogroup

207. It is the transmittal of digital signals between to or more points in a communication system.

a. Digital transmittal

b. Digital communications

c. Digital radio

d. Data communications

208. It is logically equivalent to making telephone call through the DDD network except no direct end-to-end connection is made

a. Normal call

b. Completed call

c. Logical call

d. Virtual call

209. It is proposed network designed by major telephone companies in conjunction with the ITU-T with the intent of providing worldwide telecommunications support for voice, data, video and facsimile information within the same network

a. ISDN

b. Broadband communications

c. ATM

d. Ethernet

210. Full duplex operation

a. requires two pair of cables

b. can transfer data in both directions at once

c. requires modems at both ends of the circuit

d. all of these

211. The most widely used data communications code is

a. Morse code

b. ASCII

c. Baudot

d. EBCDIC

212. Ten bit error occurs in two million transmitted. The bit error rate is

a. 2 x 10^-5

b. 5 x 10^-5

c. 5 x 10^-6

d. 2 x 10^-6

213. It is a type of FSK where the mark and space frequencies are synchronized with the input binary rate

a. QFSK

b. GFSK

c. CPFSK

d. GSK

214. A form of digital modulation similar to PSK except the digital information is contained in both the amplitude and the phase of the transmitted carrier.

a. ASK

b. FSK

c. QAM

d. PSK

215. For the 16-PSK and a transmission system with a 10kHz bandwidth, determine the maximum bit rate

a. 40,000 bps

b. 80,000 bps

c. 20,000 bps

d. 16,000 bps

216. It is an empirical record of a system’s actual bit error performance.

a. probability of error

b. error detection

c. error control

d. bit error rate

217. It is a function of the carrier-to-noise power ratio and the number of possible encoding conditions used

a. probability of error

b. error detection

c. error control

d. bit error rate

218. It is used to compare two or more digital modulation systems that use different transmission rates, modulation scheme or encoding techniques

a. Energy per b it-to-noise power density ratio

b. Noise power density

c. Power density ratio

d. Carrier-to-noise ratio

219. Indicate which of the following is not a binary code

a. Morse

b. Baudot

c. CCITT-2

d. ARQ

220. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is

a. 2

b. log 16 base 10

c. 8

d. 4

221. The type of modulation most often used with direct-sequence spread spectrum is

a. QAM

b. SSB

c. FSK

d. PSK

222. Indicate the false statement. In order to combat noise,

a. the channel bandwidth may be increased

b. redundancy may be used

c. the transmitted power may be increased

d. the signaling rate may be reduced

223. Which of the following is not commonly used method of error detection?

a. Parity

b. BCC

c. CRC

d. redundancy

224. Quantizing noise occurs in

a. time-division multiplex

b. frequency-division multiplex

c. pulse-code modulation

d. pulse-width modulation

225. In order to reduce quantizing noise, one must

a. increase the number of standard amplitudes

b. send pulses whose sides are more nearly vertical

c. use an RF amplifier at the receiver

d. increase the number of samples per second

226. Companding is used

a. to overcome quantizing noise in PCM

b. in PCM transmitters, to allow amplitude limiting in the receiver

c. to protect small signals in PCM form quantizing distortion

d. in PCM receivers, to overcome impulse noise

227. Transmitting data as serial binary word is called _______.

a. digital communications

b. quantizing

c. PAM

d. PCM

228. Emphasizing low-level signals and compressing higher level signals is called

a. quantizing

b. companding

c. pre-emphasis

d. sampling

229. Which circuit is most common to both frequency-hopping and direct-sequence spread spectrum transmitters?

a. correlator

b. frequency synthesizer

c. PSN code generator

d. Sweep generator

230. One of the most important aspect of any communication system because it is costly and limited

a. bandwidth

b. equipments

c. time

d. personnel

231. It consist essentially of sampling analog information signals and then converting those samples into discreet pulses of transporting the pulses from the source to destination over a physical transmission medium

a. Pulse modulation

b. Amplitude modulation

c. Frequency modulation

d. Digital modulation

232. He is credited with inventing PCM in 1937

a. N. S. Kapany

b. A. H. Reeves

c. E. H. Alpine

d. A. C. S. Van Heel

233. Data communications uses

a. Analog methods

b. Digital methods

c. All of these

d. None of these

234. An integrated circuit that performs the PCM encoding and decoding functions

a. Codec

b. Modem

c. Muldem

d. Digital-to-analog converter

235. A synchronous transmission usually begins with which character?

a. SYN

b. STX

c. SOH

d. ETB

236. A theory that establishes the minimum sampling rate that can be used for a given PCM systems

a. Nyquist sampling theorem

b. Nyquist minimum bandwidth

c. Nyquist minimum bandwidth

d. Any of these

237. Sixteen different levels (symbols) are used to encode binary data. The channel bandwidth is 36 MHz. The maximum channel capacity is

a. 18 Mbps

b. 72 Mbps

c. 288 Mbps

d. 2.176 Gbps

238. Assigning PCM codes to absolute magnitudes

a. Coding

b. Quantizing

c. Sampling

d. Any of these

239. A popular PC protocol is

a. Parity

b. Xmodem

c. CRC

d. LRC

240. It is the ratio of the largest possible magnitude to the smallest possible magnitude that can be decoded by the digital-to-analog converter in the receiver

a. Coding efficiency

b. Companding

c. Pre-emphasis

d. Dynamic range

241. Devices used for digitizing speech signals only

a. codec

b. muldem

c. vocoders

d. modem

242. What is the minimum bandwidth required to transmit a 56 kbps binary signal with no noise?

a. 14 kHz

b. 56 kHz

c. 28 kHz

d. 112 kHz

243. Type of PCM that uses single-bit PCM code to achieve digital transmission of analog signals

a. Adaptive delta modulation

b. Pulse code modulation

c. Differential modulation

d. Delta modulation

244. It is a delta modulation system where the step size of the digital-to-analog converter is automatically varied, depending on the analog input signal.

a. Adaptive Delta Modulation

b. PCM

c. Differential modulation

d. Delta modulation

245. A QAM modulator does not use ____.

a. XNOR

b. Bit Splitter

c. Balanced modulator

d. 2-to-4 level converter

246. It is a form of phase-division multiplexing where two data channels modulate the same carrier frequency that is shifted 90 degrees in phase.

a. PSK

b. FSK

c. QAM

d. ASK

247. One eight-bit PCM code is called ______.

a. FDM frame

b. TDM time slot

c. TDM frame

d. FDM time slot

248. It is communications system that uses digital pulse rather than analog signals to encode information

a. Digital carrier system

b. Digital baseband system

c. Digital service system

d. Digital broadband system

249. A special device that upgrades signals from one level to a higher level of the hierarchy in multiplexing

a. Muldem

b. Vocoder

c. Modem

d. Codec

250. A transmission of binary data which involves the transmission of only a single non-zero voltage level.

a. Unipolar

b. Bipolar

c. Polar

d. Non-return to zero

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