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 V of the Series
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
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