# Multiple Choice Questions and Answers on Integrated Circuits

**1) Which among the following is/are the feature/s characteristic/s of an integrated op-amp?**

**a.** Small size

**b.** High reliability

**c.** Low cost & less power consumption

**d.** All of the above

**ANSWER: All of the above**

**2) In a typical op-amp, which stage is supposed to be a dual-input unbalanced output or single-ended output differential amplifier?**

**a.** Input stage

**b.** Intermediate stage

**c.** Output stage

**d.** Level shifting stage

**ANSWER: Intermediate stage**

**3) In differential mode of op-amp, if output voltage is equal to the difference between outputs of individual transistors, its amplitude will be _______the amplitude of signal voltage yielded at collector to ground.**

**a.** twice

**b.** thrice

**c.** four times

**d.** one-fourth times

**ANSWER: twice**

**4) In a differential amplifier, the configuration is said to be an ‘unbalanced output’, if ________**

**a.** Output voltage is measured between two collectors

**b.** Output is measured with respect to ground

**c.** Two input signals are used

**d.** All of the above

**ANSWER: Output is measured with respect to ground**

**5) Input offset current is basically defined as the algebraic ______ the base current of two transistors.**

**a.** sum of

**b.** difference between

**c.** product of

**d.** division of

**ANSWER: difference between**

**6) Unipolar belongs to ________technology/ies of integrated circuits.**

**a.** Hybrid

**b.** Monolithic

**c.** Both a and b

**d.** None of the above

**ANSWER: Monolithic**

**7) Which among the following belong to the category of bipolar technology?**

A. JFET

B. MOSFET

C. P-N junction isolation

D. Di-electric isolation

**a.** A & B

**b.** B & C

**c.** C & D

**d.** A & D

**ANSWER: C & D**

**8) Which op-amp technology/ies exhibit/s low current sourcing/ sinking capacity?**

**a.** Bipolar op-amp

**b.** CMOS op-amp

**c.** BICMOS op-amp

**d.** All of the above

**ANSWER: CMOS op-amp**

**9) How many stages are involved in bipolar op-amp?**

**a.** 2

**b.** 3

**c.** 4

**d.** 6

**ANSWER: 3**

**10) In op-amps, which type of noise occurs due to discrete flow of current in the device?**

**a.** Shot noise

**b.** Burst noise

**c.** Thermal noise

**d.** Flicker noise

**ANSWER: Shot noise**

**11) Which among the following is a nonlinear application of op-amp?**

**a.** V to I converter

**b.** Comparator

**c.** Precision rectifier

**d.** Instrumentation amplifier

**ANSWER: Precision rectifier**

**12) What is the feedback factor of voltage follower circuit?**

**a.** Zero

**b.** Unity

**c.** Infinity

**d.** Between zero & one

**ANSWER: Unity**

**13) For non-inverting adder, which theorem is applicable to determine the expression for output voltage?**

**a.** Thevenin’s

**b.** Norton’s

**c.** Miller’s

**d.** Superposition

**ANSWER: Superposition**

**14) Which among the following is/are the requirement/s of an instrumentation amplifier?**

**a.** High slew rate

**b.** High input resistance

**c.** High CMRR

**d.** All of the above

**ANSWER: All of the above**

**15) For a temperature controller circuit comprising instrumentation amplifier, which among the following is adopted as a temperature sensor?**

**a.** Thermistor

**b.** Sensistor

**c.** Thyristor

**d.** Thermocouple

**ANSWER: Thermistor**

**16) Which parameter/s is/are used to indicate the speed of a comparator?**

**a.** Response Time

**b.** Propagation Delay

**c.** Both a and b

**d.** None of the above

**ANSWER: Both a and b**

**17) Basically, response time is defined as the time acquired by the comparator to accomplish ______of its transition corresponding to the voltage step at the input.**

**a.** 20%

**b.** 50%

**c.** 70%

**d.** 100%

**ANSWER: 50%**

**18) For an ideal comparator, what should be the value of the response time? **

**a.** Zero

**b.** Unity

**c.** Infinite

**d.** Unpredictable

**ANSWER: Zero**

**19) Zero crossing detector circuit plays a crucial role in conversion of input sine wave into a perfect _________at its output.**

**a.** triangular wave

**b.** square wave

**c.** saw-tooth wave

**d.** pulse wave

**ANSWER: square wave**

**20) For reducing the effects of input offset in comparator, what would be the possible value of input offset voltage?**

**a.** Low

**b.** Moderate

**c.** High

**d.** None of the above

**ANSWER: Low**

**21) In weighted resistor DAC, how many resistor/s per bit is/are required?**

**a.** One

**b.** Two

**c.** Three

**d.** Four

**ANSWER: One**

**22) In DAC, resolution increases with the _________ in number of bits.**

**a.** Increase

**b.** Decrease

**c.** Constant

**d.** None of the above

**ANSWER: Increase**

**23) Which among the following characteristics of D/A converter occur/s due to resistor and semiconductor aging?**

**a.** Speed

**b.** Settling time

**c.** Long term drift

**d.** Supply rejection

**ANSWER: Long term drift**

**24) In DACs, which type of error/s specify/ies the amount by which the actual output of DAC differ from ideal straight line transfer characteristics?**

**a.** Linearity error

**b.** Offset error

**c.** Gain error

**d.** All of the above

**ANSWER: Linearity error**

**25) Offset error is basically defined as the non-zero level of analog output especially when all the digital inputs are ____. **

**a.** 0

**b.** 1

**c.** Both a and b

**d.** None of the above

**ANSWER: 0**

**26) Basically, PLL is used to lock _______**

**a.** Its output frequency

**b.** Phase to the frequency

**c.** Phase of the input signal

**d.** All of the above

**ANSWER: All of the above**

**27) In communication circuits, PLL is currently applicable for __________**

**a.** Demodulation applications

**b.** Tracking a carrier or synchronizing signal

**c.** Both a and b

**d.** None of the above

**ANSWER: Both a and b**

**28) In the locked state of PLL, the phase error between the input & output is _________.**

**a.** Maximum

**b.** Moderate

**c.** Minimum

**d.** All of the above

**ANSWER: Minimum**

**29) Once the phase is locked, the PLL tracks the variation in the input frequency. This indicates that _____**

**a.** Output frequency changes by same amount as that of input frequency

**b.** Output frequency does not change as that of input frequency

**c.** There is no relation between input & output frequencies

**d.** None of the above

**ANSWER: Output frequency changes by same amount as that of input frequency**

**30) In PLL, the capture range is always _________the lock range.**

**a.** Greater than

**b.** Equal to

**c.** Less than

**d.** None of the above

**ANSWER: Less than**

**31) Which among the following factors affect/s the output voltage of a regulated power supply?**

**a.** Load current

**b.** Input voltage

**c.** Temperature

**d.** All of the above

**ANSWER: All of the above**

**32) Which performance parameter of a regulator is defined as the change in regulated load voltage due to variation in line voltage in a specified range at a constant load current?**

**a.** Load regulation

**b.** Line regulation

**c.** Temperature stability factor

**d.** Ripple rejection

**ANSWER: Line regulation**

**33) The % load regulation of a power supply should be ideally ________ & practically _______.**

**a.** zero, small

**b.** small, zero

**c.** zero, large

**d.** large, zero

**ANSWER: zero, small**

**34) Switching regulators are series type regulators, which has ______ power dissipation & ______ efficiency.**

**a.** increased, increased

**b.** increased, reduced

**c.** reduced, increased

**d.** reduced, reduced

**ANSWER: reduced, increased**

**35) In a linear IC voltage regulator, series pass transistor always operates in ______ region.**

**a.** Active

**b.** Saturation

**c.** Cut-off

**d.** All of the above

**ANSWER: Active**

**36) Which among the following compression techniques is/are intended for still images?**

**a.** JPEG

**b.** H.263

**c.** MPEG

**d.** All of the above

**ANSWER: JPEG**

**37) Which lossy method for audio compression is responsible for encoding the difference between two consecutive samples?**

**a.** Silence Compression

**b.** Linear Predictive Coding (LPC)

**c.** Adaptive Differential Pulse Code modulation (ADPCM)

**d.** Code Excited Linear Predictor (CELP)

**ANSWER: Adaptive Differential Pulse Code modulation (ADPCM)**

**38) Which coding technique/s exhibit/s the usability of fixed length codes?**

**a.** Lempel Ziv

**b.** Huffman

**c.** Both a and b

**d.** None of the above

**ANSWER: Lempel Ziv**

**39) Which among the following is used to construct the binary code that satisfies the prefix condition?**

**a.** Information Rate

**b.** Noiseless Channel

**c.** Channel Coding Theorem

**d.** Kraft Inequality

**ANSWER: Kraft Inequality**

**40) Information rate basically gives an idea about the generated information per _____ by source.**

**a.** Second

**b.** Minute

**c.** Hour

**d.** None of the above

**ANSWER: Second**

**41) Which approach plays a cardinal role in supporting the results obtained regarding the information capacity theorem?**

**a.** Line Packing

**b.** Volume Packing

**c.** Sphere Packing

**d.** All of the above

**ANSWER: Sphere Packing**

**42) In sphere packing, where is the received code vector with added noise located? **

**a.** Inside the sphere

**b.** Outside the sphere

**c.** On the boundary (circumference) of sphere

**d.** All of the above

**ANSWER: Inside the sphere**

**43) If a noiseless channel bandlimited to 5 kHz is sampled every 1msec, what will be the value of sampling frequency?**

**a.** 250 samples/sec

**b.** 500 samples/sec

**c.** 800 samples/sec

**d.** 1000 samples/sec

**ANSWER: 1000 samples/sec**

**44) Assuming that the channel is noiseless, if TV channels are 8 kHz wide with the bits/sample = 3Hz and signalling rate = 16 x 10 ^{6} samples/second, then what would be the value of data rate?**

**a.** 16 Mbps

**b.** 24 Mbps

**c.** 48 Mbps

**d.** 64 Mbps

**ANSWER: 48 Mbps**

**45) On which factor/s do/does the channel capacity depend/s in the communication system?**

**a.** Bandwidth

**b.** Signal to Noise Ratio

**c.** Both a and b

**d.** None of the above

**ANSWER: Both a and b**

**46) Which amount the following is capable of correcting any combination of three or fewer errors random errors in a block of 23 bits?**

**a.** Hamming codes

**b.** Interleaved code

**c.** Repetition codes

**d.** Golay code

**ANSWER: Golay code**

**47) For a (6,4) block code where n = 6, k = 4 and d _{min} = 3, how many errors can be corrected by this code?**

**a.** 0

**b.** 1

**c.** 2

**d.** 3

**ANSWER: 1**

**48) In Repetition Code, how many information bit/s is/are present in addition to n-1 parity bits?**

**a.** One

**b.** Two

**c.** Four

**d.** Eight

**ANSWER: One**

**49) On which factor/s do/does the error probability depend/s after decoding?**

**a.** Number of error vectors

**b.** Error probability of symbol transmission

**c.** Both a and b

**d.** None of the above

**ANSWER: Both a and b**

**50) Which buffer size is required by the interleaved codes at the transmitter for the accumulation of λ code words?**

**a.** Small

**b.** Medium

**c.** Large

**d.** All of the above

**ANSWER: Large**

**51) For the generation of a cyclic code, the generator polynomial should be the factor of _____**

**a.** x^{n} + 1

**b.** x^{n} – 1

**c.** x^{n} /2

**d.** x^{2n/3}

**ANSWER: x ^{n} + 1**

**52) Consider the assertions related to decoding process of cyclic code. Which among the following is a correct sequence of steps necessary for the correction of errors?**

A. Syndrome determination after the division of r(x) & g(x)

B. Addition of error pattern to received code word

C. Selection of error pattern corresponding to the syndrome

D. Preparation of table comprising error patterns and syndromes

**a.** A, B, C, D

**b.** B, A, D, C

**c.** C, B, D, A

**d.** D, A, C, B

**ANSWER: D, A, C, B**

**53) Which among the below stated logical circuits are present in encoder and decoder used for the implementation of cyclic codes?**

A. Shift Registers

B. Modulo-2 Adders

C. Counters

D. Multiplexers

**a.** A & B

**b.** C & D

**c.** A & C

**d.** B & D

**ANSWER: A & B**

**54) Which among the following error detecting technique is supposed to be parity bit associated with character code?**

**a.** LRC

**b.** VRC

**c.** Both a and b

**d.** None of the above

**ANSWER: VRC**

**55) In register contents at decoder, the syndrome register consists of syndrome after all bits of received vector are clocked into the decoder ________.**

**a.** Input

**b.** Output

**c.** Both a and b

**d.** None of the above

**ANSWER: Input**

**56) If the errors are corrected at _______end/s, it is known as ‘Forward Error Correction’ (FEC).**

**a.** Transmitter

**b.** Receiver

**c.** Both a and b

**d.** None of the above

**ANSWER: Receiver**

**57) In Frame Check Sequence (FCS), which code is used if character length is 6 bit and generates 12 bit parity check bits?**

**a.** CRC-12

**b.** CRC-16

**c.** CRC-32

**d.** CRC-CCITT

**ANSWER: CRC-12**

**58) Decoding of RS code comprises the determination of error _______**

A. position

B. magnitude

C. angle

D. frequency

**a.** A & B

**b.** C & D

**c.** A & C

**d.** B & D

**ANSWER: A & B**

**59) In RS code, the length is ____less than number of symbols in symbol set (q).**

**a.** One

**b.** Two

**c.** Three

**d.** Infinite

**ANSWER: One**

**60) In Minimum Distance Separable (MDS) codes, the minimum distance is one more than the number of _________.**

**a.** Information bits

**b.** Symbol bits

**c.** Parity check bits

**d.** None of the above

**ANSWER: Parity check bits**

**61) In Trellis diagram, what do/does the horizontal axis represent/s?**

**a.** Continuous time

**b.** Discrete time

**c.** Sampled time

**d.** All of the above

**ANSWER: Discrete time**

**62) For the 4 states of an encoder on vertical axis of Trellis diagram, what do/does the solid line indicate/s?**

**a.** ‘0’ input

**b.** ‘1’ input

**c.** Both a and b

**d.** None of the above

**ANSWER: ‘0’ input**

**63) Which decoding method involves the evaluation by means of Fano Algorithm?**

**a.** Maximum Likelihood Decoding

**b.** Sequential Decoding

**c.** Both a and b

**d.** None of the above

**ANSWER: Sequential Decoding**

**64) For a received sequence of 6 bits, which decoding mechanism deals with the selection of best correlated sequence especially by correlating the received sequence and all permissible sequences?**

**a.** Soft Decision Decoding

**b.** Hard Decision Decoding

**c.** Both a and b

**d.** None of the above

**ANSWER: Soft Decision Decoding**

**65) To obtain the transfer function of a convolutional code, the splitting of all-zero state takes place into ___**

A. starting state

B. first return to all-zero state

C. in-between state

**a.** A & B

**b.** B & C

**c.** A & C

**d.** None of the above

**ANSWER: A & B**

**66) The distance between each symbol in given sequence and reference sequence is known as _______.**

**a.** Euclidean Distance

**b.** Distance between sequences

**c.** Manmattan Distance

**d.** Hamming Distance

**ANSWER: Distance between sequences**

**67) d _{free} is defined as the Euclidean distance of coded signal in terms of _________ possible distance between all allowed sequences.**

**a.** smallest

**b.** largest

**c.** average

**d.** constant

**ANSWER: smallest**

**68) For designing trellis code, the emphasis must be on maximizing __________**

**a.** Euclidean distance between code vectors

**b.** Hamming distance of error correcting codes

**c.** Both a and b

**d.** None of the above

**ANSWER: Euclidean distance between code vectors**

**69) For designing a communication system, which among the following parameters should be maximum?**

A. Transmission rate

B. Received signal-to-noise ratio

C. Error probability

D. Bandwidth requirement

**a.** A & B

**b.** C & D

**c.** A & C

**d.** B & D

**ANSWER: A & B**

**70) For fixed symbol rate, increase in bits/symbol ultimately improves r _{b}/B bits/s/Hz & hence, regarded as _____.**

**a.** Power efficiency

**b.** Spectral efficiency

**c.** Transmission efficiency

**d.** Modulation efficiency

**ANSWER: Spectral efficiency**