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Analog Communication Question & Answers

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This article lists 100+ Analog Communication MCQs for engineering students. All the Analog Communication Questions & Answers given below includes solution and link wherever possible to the relevant topic.

Communication means sharing information from one location to another. For example; mobile conversations, video lectures, etc. Samuel Morse invented Telegraph by using the morse code in 1837. The first revolution came in the world of communication after the telegraph and the telephone was invented by A.Graham bell in 1875.

This was a wired communication that would be a sender or information source, input transducer, transmitter, channel, receiver, output transducer, and an information receiver. Examples of analog communication are amplitude modulation, frequency modulation, phase modulation, pulse amplitude, pulse width, and pulse position modulation.

The benefit of having analog communication is, it is a simple type of communication technique, which uses less bandwidth, and multiplexing is easy, so we can just superimpose the signals in different frequencies of the carrier.

1). The square law modulator consists _______
HintThe square law modulator consists adder which is adding carrier and modulating signal, the non-linear device then after the signal from the non-linear device passed to a bandpass filter.
Read more about Band Pass Filter.
2). The amplitude modulation is the process in which amplitude of the carrier signal changes with respect to _____________ signal
HintThe amplitude of the carrier signal changes with respect to modulating signal in the amplitude modulation
Read more about Amplitude Modulation.
3). The full-duplex is a _________ system
HintThe full-duplex is a bidirectional communication system, in this system the transistor and receiver can send the signal at the same time. Example: telephone communication system
4). Why the carrier signal doesn’t carry any signal?
HintThe carrier signal doesn’t carry any signal because the parameters of the carrier signal are constant throughout the time or throughout the length
5). The standard form of PAM is _________
HintThe standard form of PAM is Pulse Amplitude Modulation, it is one type of modulation in analog
Read more about Pulse Amplitude Modulation.
6). The half-duplex is a _________ system
HintThe half-duplex is a bidirectional communication system, but it is not a fully bidirectional communication system because at one time it can send either receive. Example: Wacky Talky
7). The antenna height is equal to ______
HintThe antenna height h=λ/4, where λ is the wavelength of the transmitted signal and h is the height of the antenna
8). The advantages of the modulation are _______
HintIn modulation the energy of the carrier is high, noise can be reduced, SNR would be improved and multiplexing is possible, these are the advantages of the modulation
Read more about Modulation.
9). The simplex system is a _________ system
HintThe simplex system is a unidirectional communication system, in unidirectional system communication happens only in one direction. Example: broadcasting
10). How many types of electric communication systems are there?
HintThere are three types of communication systems they are simplex system, half-duplex system, and full-duplex communication system.
11). Who invented first wireless radio wave over 1700 miles?
HintThe first wireless radio wave over 1700 miles discovered by Guglielmo Marconi in the year 1901
12). _________ is the process in which amplitude of the carrier signal changes with respect to message or modulating signal
HintAmplitude modulation is the process in which the amplitude of the carrier signal changes with respect to message or modulating signal
13). The first wireless communication over short distance discovered by ________
HintThe first wireless communication over a short distance discovered by Oliver Lodge in 1894
Read more about Wireless Communication.
14). The envelope detector is __________
HintThe envelope detector is a very simple type of detector and very effective for the detection of the narrowband amplitude modulation signal
15). The number of bits conveyed or processed for unit time is called ________
Hint The number of bits conveyed or processed for unit time is called bit rate
16). Who invented super heterodyne receiver?
HintThe super heterodyne receiver is discovered by Armstrong in 1918
17). In ______ modulation the phase of the carrier signal is modulated by the message signal
Hint In phase modulation the phase of the carrier signal is modulated by the message signal, it is one type of angle modulation
18). Who invented first frequency modulation demodulation?
HintThe first frequency modulation demodulation scheme is invented by Armstrong in 1993
19). In ______ modulation the frequency of the carrier signal is modulated by the message signal
HintIn frequency modulation, the frequency of the carrier signal is modulated by the message signal
20). Who did PCM encoding of speech signal for digital transmission?
HintThe PCM encoding of speech signal for digital transmission is done by Alec Reeves in 1937
21). _________ noise is a static kind of noise which is generated due to electric disturbances
HintThe atmospheric noise is static noise, example thunderstorm produces electrical disturbances in the air & the effects of this electrical disturbance the signal in a communication channel
22). The industrial noise occurs in the range around ________
HintThe industrial noise is basically a manmade noise, it occurs in the range around 1MHz-600MHz
23). The area over which cosmic noise effects most is around ______
HintThe area over which cosmic noise effects is around 20MHz-120MHz in a communication channel
24). What are the external noise?
Hint The external noise is the noises which are generated outside the receiver or an amplifier, the atmospheric, industrial, and extraterrestrial noise are the external noises
25). The double side band suppressed carrier comes under _____ modulation
Hint In amplitude modulation technique, we have some problems regarding bandwidth as well as transmitted power, and the problem is solved by DSB-SC (Double Side Band – Suppressed Carrier)
26). In baseband signal the audio frequency signal range is around ________
HintIn baseband signal, the audio frequency signal range is around 0-20 kHz
27). What are the noises comes under internal noise _____
HintThe resistor noise, shot noise, and transient noises are comes under internal noise
28). In synchronous detector _______ errors are generated
Hint In a synchronous detector both phase and frequency type errors generated because of the synchronization of the local oscillator
29). ___________ type of errors are generated in envelope detector
HintThe negative clipping and diagonal envelope problems arised in the envelope detector because of two things one is because of modulating index & another one is because of RC filter which is used in LPF
30). The complexity is _________ in synchronous detection
HintThe complexity is high in synchronous detector because the phase lock loop, local oscillator, synchronization, and so many things are required

Analog Communication Important MCQ’s

31). In base band signal the frequency range of amplitude modulation is around ________
HintIn baseband signal, the frequency range of amplitude modulation is around 550KHz-1650KHz
32). In envelope detection the complexity is ____________
HintThe envelope detector is made by a diode, resistance, and capacitance so it is very simple
33). The side band cancellation in filter method is done by using ______
HintThe sideband cancellation in the filter method is done by using filter
34). The frequency range of modulating signal in narrow band frequency modulation is between _________
HintThe frequency range of modulating signal in narrow-band frequency modulation is between 30 Hz - 3 kHz
35). When negative changes is happening to AF voltage the junction capacitance will actually _______ in varactor diode modulator
HintWhen negative changes are happening to AF voltage the junction capacitance will actually increase in the varactor diode modulator, when junction capacitance increases the frequency will reduce
36). How much is the frequency band in GSM?
HintThe frequency band in GSM is around 900 MHz
37). In base band signal the video frequency signal range is around ________
HintIn baseband signal, the video frequency signal range is from 0-55MHz
38). In pass band signal, the frequency range of frequency modulation is around _________
HintIn passband signal, the frequency range of frequency modulation is around 88 MHz-100MHz
39). The frequency band range of Code Division Multiplexing Access in pass band signal is around _______
HintThe frequency band range of Code Division Multiplexing Access in passband signal is around 1800MHz
40). In medium modulating index the modulation index is ________
HintIn medium modulating index, the modulation index is between one to ten
41). The side band cancellation in phase shift method is done by using ______
HintThe selectivity, sensitivity, and fidelity are the characteristics of the receiver, where selectivity rejects unwanted signal, the sensitivity of the receiver is good, and fidelity is used to avoid distortion
43). In super heterodyne receiver, at high frequency the ______
HintIn the superheterodyne receiver, at high frequency, processing and transmission of the signal should be done, and the bandwidth is low
44). The maximum deviation in narrow band frequency modulation is around _________
HintThe maximum deviation in narrow-band frequency modulation is around 5 kHz
45). When several signals are multiplexed in a frequency domain then the modulation is called ________
HintWhen several signals are multiplexed in a frequency domain then the modulation is called Frequency Division Multiplexing (FDM)
46). When figure of merit is less than one, the output of signal to noise ratio is _______ the input of signal to noise ratio
HintWhen the figure of merit is greater than one, the output of a signal to noise ratio is less than the input of a signal to noise ratio
47). The levels in differential pulse code modulation are ______
HintThe levels in DPCM are less than the pulse code modulation because the number of bits in DPCM is less than the PCM
48). _______ quantizer minimizes the quantization error
HintThe LLOYD-Max quantizer is an optimal quantizer that minimizes the quantization error
49). The quantization error can be defined as _______
HintThe quantization error can be defined as q=Q(m)-m, where q is the quantization error, Q is the quantization sample value, and m is the true sample value
50). What are the advantages of the angle modulation over amplitude modulation?
HintThe advantages of angle modulation over amplitude modulation are noise reduction happens, system fidelity should improve, and the use of power is efficient.
51). What are the applications of Angle modulation?
HintRadio broadcasting, tv sound transmission, cellular radio, etc are some applications of Angle modulation
52). How many categories does the modulation index have?
HintThe modulation index is divided into three categories they are high, low, and medium modulation index
53). In lower modulating index the modulation index is ________
HintIn lower modulating index the modulation index is less than one
54). In a higher modulating index the modulation index is ________
HintIn a higher modulating index the modulation index is greater than ten
55). When several signals are multiplexed in a time domain then the modulation is called ________
HintWhen several signals are multiplexed in a time domain then the modulation is called Time Division Multiplexing (TDM)
56). Which noise comes under internal noise?
HintThe internal noise is the noises that are generated inside the receiver or an amplifier, the resistor, shot, and transient noise are the internal noises
57). The SNR in delta modulation is ______
HintThe SNR in delta modulation is poor because the step size is fixed and the number of levels used in DM is two so there was more probability of error
58). The quantization is a many to one mapping, in which all sample values in a particular interval are mapped to a __________
HintThe quantization is a many to one mapping, in which all sample values in a particular interval are mapped to a quantization level
59). In _________ modulation, frequency or phase of carrier signal changes with respect to modulating signal
HintIn angle modulation, frequency or phase of carrier signal changes with respect to modulating signal
60). The maximum deviation in wideband frequency modulation is around _________
HintThe maximum deviation in wideband frequency modulation is around 75 kHz

Analog Communication MCQ’s for Interviews

61). The frequency range of modulating signal in wideband frequency modulation is between _________
HintThe frequency range of modulating signal in wideband frequency modulation is between 30 Hz - 15 kHz
62). The SSB frequency range is __________ in filter method
HintThe frequency is high in the SSB filter method, the reason is filter size depends on the frequency operator as well as stability of frequency that even depends on the filter
63). The bandwidth for transmission in pulse code modulation is __________
HintThe bandwidth for transmission in pulse code modulation is higher than the differential pulse code modulation because the number of bits is higher than the DPCM
64). The formula of amplifier is given by ___________
HintThe ratio of noise at the amplifier will be F-1/F
Read more about Amplifier.
65). When the figure of merit is greater than one, the output of a signal to noise ratio is _______ the input of a signal to noise ratio
HintWhen the figure of merit is greater than one, the output of a signal to noise ratio is greater than the input of a signal to noise ratio
66)________ is a differential modulation
HintThe delta modulation is a differential modulation because it encodes the difference of signal samples
Read more about Delta Modulation.
67). The additive white Gaussian noise _______
HintThe additive white Gaussian noise requires infinite power because it has uniform power spectral density for each frequency value up to infinity, so it is practically unrealizable
68). The thermal noise _______
Hint The thermal noise requires finite power
69). The number of bits in DPCM is _______
HintThe number of bits in DPCM is less than PCM because the error functions are very less in dynamic range because there was more correlation in the adjacent samples
70). The levels in PCM are ______
HintThe levels in PCM depend on the number of bits, if the number of bits is more than the levels are more
71). In which case the step size is not fixed?
HintIn Adaptive Delta Modulation, the step size is not fixed because that depends upon the message signal, whereas in other modulations the step size is fixed
Read more about Adaptive Delta Modulation.
72). The bandwidth for transmission in differential pulse code modulation is __________
Hint The bandwidth for transmission in differential pulse code modulation is lower than the pulse code modulation because the number of bits is lower than PCM
73). When positive changes are happening to AF voltage the junction capacitance will actually _______ in varactor diode modulator
HintWhen positive changes are happening to AF voltage the junction capacitance will reduce in the varactor diode modulator, when junction capacitance reduces the frequency will increase
74). The quantization error in PCM is ________
HintThe quantization error in PCM is present depends upon the levels, if the number of levels is more the quantization error will be less
75). The SNR in PCM is ______
HintThe SNR in pulse code modulation is good because the signal power is good and it is less affected by noise
76). In a uniform quantizer with an even number of quantization levels, the quantizer characteristics arise from __________
HintIn a uniform quantizer with an even number of quantization levels, the quantizer characteristics arise from –Δ/2 to +Δ/2 at m=0. This is therefore turned as a mid-rise quantizer
77). The SNR in adaptive delta modulation is ______
HintThe SNR in adaptive delta modulation is better than DM because the variable step size is used in ADM so it is better than DM
78). The quantization error in DPCM is ________
HintThe quantization error in DPCM is less than the PCM because the number of levels is less than the pulse code modulation.
79). Analog communication uses _______ types of signals.
HintAnalog communication uses a continuous type of signals.
80). In which technique data is transmitted using continuous signals?
HintAnalog communication is a technique that uses continuous signals to transmit data that includes voice, image, video, etc.
81). An analog signal is _______ signal continuous in both time and amplitude.
HintAn analog signal is a variable signal that is continuous in both time and amplitude.
82). In which technique physical transfer of data over a point to point or point to multi-point transmission medium is done?
HintDigital communication is a technique where physical data transfer is done over a point to point or point to multi-point transmission medium is done.
83). Which of the following are the examples of analog communication technology?
HintAnalog communication technology includes photocopiers, audiotapes, old-landlines, etc.
84). Which of the following are the examples of digital communication technology?
HintDigital communication technology includes emails, wikis.
85). Digital communication is represented in ______ form.
HintDigital communication is represented in o’s and 1’s form, where 0 is a low signal and 1 is a high signal.
86). An analog signal is represented in ______ form.
HintAn analog signal is represented in both the time domain and frequency domain.
87). What is the serious issue in analog communication compared to digital communication?
HintThe serious issue in analog communication compared to digital communication is that it has noise at the maximum amount of times.
88). In analog communication electronic noise and disturbance is introduced into transmission channel results in _______.
HintIn analog communication electronic noise and disturbance are introduced into the transmission channel reduces the signal to noise ratio.
89). Analog communication contains _______ number of components.
HintAnalog contains 6 major components namely, Information source, Input transducer, transmitter, receiver, destination.
90). What is the function of an information source?
HintInformation source is an input building block of analog communication, where its function is to generate information.

Analog Communication Important MCQ’s with Hints

91). Messages generated in an input source block of analog communication can be in which form?
HintMessages generated in an input source block of analog communication can be in words, a group of words, signals form.
92). What is the function of a transducer?
HintA transducer is the second most component of analog communication, where the output of information source message is given as input to a transducer. The main functionality of a transducer is to convert energy from one form to another form.
Read more about Transducer.
93). Radio broadcasting converts ______ into ______ using transducer.
HintRadio broadcasting converts Nonelectrical into electrical using a transducer. It can be converting sound waves into an electrical signal.
94). What is the function of the transmitter?
HintThe function of the transmitter is to Transmits signals over the channel.
95). Which technique is used in the transmitter?
HintIn a transmitter, modulation technique is used. where it is a process of superimposition of message signal over higher frequency carrier signal.
96). What is the functionality of a channel?
HintThe functionality of a channel is to the transmitter is to transmit a message from transmitter to receiver.
97). How many types of channels are used in analog communication components?
HintTwo types of channels are used in analog communication components, are point to point channel and broadcast channel.
98). Which of the following channels are used in analog communication?
HintPoint to point channel and broadcast channel are used in analog communication.
99). Which of the following are examples of point to point channel?
HintSome of the examples of the point-to-point channels are wire lines, microwave links, optical fibers.
100). What is the functionality of the broadcast channel?
HintThe broadcast channel handles several incoming messages from a transmitter.
101). What is the functionality of the receiver?
HintThe functionality of a receiver is to produce an electric message from the received signal which was previously in distorted form from the channel.
102). Which technique is performed in the receiver?
HintDemodulation is performed at the receiver.
103). What is the functionality of the destination?
HintThe destination is the final block of analog communication. The output of the receiver is given as input to the destination whose functionality is to, converts an electrical signal into the original input.
104). A periodic signal is of _______ pattern with respect to time.
HintA periodic signal is of a repetitive pattern with respect to time.
105). An aperiodic signal is of _______ pattern with to time.
HintAn aperiodic signal does not repeat with respect to time. It is an irregular, non-repetitive pattern.
106). What happens to the message if the message signal characteristic is changed?
HintIf the characteristic of a message signal is altered, the message that is being transmitted is also altered.
107). A _______ frequency signal can carry a message over a long distance.
HintA high-frequency signal can carry a message over a long distance.
108). A high frequency signal is also called as ______ signal.
HintA high-frequency signal is a carrier signal, which is used to transmit a message over a channel up to a long distance.
109). In digital communication does antenna size reduces in modulation technique?
HintModulation is a process used to transmit a message signal over a long distance without any disturbance. Yes, the size of the antenna is reduced.
110). What are the types of signals used in the modulation?
HintThere are three types of signals used in modulation, namely carrier signal, modulated signal, modulating, or message signal.
111). Which of the following modulation technique is used for analog modulation?
HintIn analog communication, there are two types of modulation techniques used – continuous-wave modulation and pulse modulation.
112). Which of the following comes under continuous wave modulation?
HintA continuous-wave modulation is classified into two types namely, amplitude modulation and angle modulation. Where angle modulation is further classified as frequency modulation and phase modulation.
113). Which of the following is angle modulation?
HintAngle modulation is a continuous wave modulation which is further classified as frequency modulation and phase modulation.
114). Which of the following is pulse modulation?
HintPulse modulation is classified into two types namely, analog modulation and digital modulation.
115). Which of the following is an analog modulation?
HintAnalog modulation is classified into 3 types namely, Pulse type amplitude modulation PAM, Pulse type width modulation PWM, Pulse type position modulation PPM.
116). Which of the following is a digital modulation?
HintDigital modulation is a pulse modulation which is further classified as pulse code modulation and delta modulation.
117). How many types of modulators are present in double side band suppressed carrier?
HintThere are two types of double side band suppressed carriers namely balanced type modulator and ring-type modulator.
118). What are the components in a balanced modulator?
HintThe components in a balanced modulator are identical AM type modulator two in number, a local oscillator, and a summer. Where local oscillator and AM modulator are at the input side and summer is at the output side.
119). A ring modulator contains how many diodes?
HintA ring modulator contains 4 diodes connected in ring fashion, this modulator is used in DSBSC.
Read more about Diodes.
120). DSBSC modulators are also called as ________.
HintDSBSC modulators are also called product type modulators.
121). Pulse modulation is _______ sequence pf rectangular pulse.
HintPulse modulation is a periodic sequence.
122). Which of the following statement is true for pulse amplitude modulation PAM?
HintIf the pulse amplitude is varied with respect to instantaneous values of baseband modulating signal is called pulse amplitude modulation PAM.
123). Which of the following statement is true for pulse width modulation?
HintIf The pulse duration is varied with respect to instantaneous values of baseband modulating signal is called pulse width modulation or pulse duration modulation PWM /PDM.
124). Which of the following statement is true for pulse position modulation?
HintIf the pulse position is varied with respect to instantaneous values of baseband modulating signal it is called pulse position PPM.
125). Message signal in the time domain is represented as ________.
HintMessage signal in time domain is represented as m (t) = Am cos (2π fm t) Where m = message; Am = amplitude of message signal, fm = frequency of modulating signal, t = time.
126). Carrier signal in time domain is represented as ________.
HintCarrier signal in time domain is represented as c (t) = Ac cos ( 2π fc t), where c(t) = carrier signal in time domain, Ac = carrier signal amplitude, fc = frequency of carrier signal, t = time.
127). What is the formula for modulation index “µ” when amplitudes of modulating signal “Am” and carrier signal “Ac” is known?
HintThe formula for modulation index “µ” when amplitudes of modulating signal “Am” and carrier signal “Ac” is given as µ = Am / Ac.
128). What is the condition for perfect modulation?
HintThe condition for perfect modulation is µ = 1, where µ is the modulation index.
129). How many types of demodulators are present in a DSBSC wave?
HintThere are two types of demodulators are present in a DSBSC wave namely coherent detector and noncoherent detector.
130). If the maximum frequency is subtracted from lower frequency it is called ________.
HintIf the maximum frequency is subtracted from the lower frequency it is called bandwidth.
131). What is the bandwidth of AM wave?
HintThe bandwidth of AM wave is BW = 2fm.
132). Which type of modulators are used in AM wave generation?
HintSquare law modulator and switching modulator are used in AM wave generation.
133). Which of the following are the components of square law modulator?
HintThe components of the square law modulator are summer, square-law device, and bandpass filter.
134). Which of the following are the components of the switching modulator?
HintThe components of the switching modulator are summer, switching diode, bandpass filter.
135). The process of extracting the original message from the signal is called _______.
HintThe process of extracting the original message from the signal is called demodulation.
136). Demodulation is done at ______ side.
HintDemodulation is done at the receiver side.
137). What is the functionality of the envelope detector?
HintThe functionality of the envelope detector is to detect AM waves with high frequency.

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