Analog Communication Question & AnswersApril 23, 2021 By WatElectronics 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 _______ Adder Non-linear device Bandpass filter All of the above 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 Modulating signal Carrier signal Suppressed carrier modulating signal None of the above 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 Unidirectional communication Bidirectional communication Multidirectional communication None of the above 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 system4). Why the carrier signal doesn’t carry any signal? Frequency is constant Phase and amplitude constant Amplitude is Constant All of the above HintThe carrier signal doesn’t carry any signal because the parameters of the carrier signal are constant throughout the time or throughout the length5). The standard form of PAM is _________ Pulse Amplitude Modulation Phase Amplitude Modulation Positive Amplitude Modulation None of the above 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 Unidirectional communication Bidirectional communication Multidirectional communication None of the above 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 Talky7). The antenna height is equal to ______ h=λ/2 h=λ/8 h=λ/4 None of the above HintThe antenna height h=λ/4, where λ is the wavelength of the transmitted signal and h is the height of the antenna8). The advantages of the modulation are _______ High energy of carrier Noise can be reduced Multiplexing is possible All of the above 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 Unidirectional communication Bidirectional communication Multidirectional communication None of the above HintThe simplex system is a unidirectional communication system, in unidirectional system communication happens only in one direction. Example: broadcasting10). How many types of electric communication systems are there? One Two Three Four 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? Armstrong Oliver Lodge Goglielmo Marconi Samuel Morse HintThe first wireless radio wave over 1700 miles discovered by Guglielmo Marconi in the year 190112). _________ is the process in which amplitude of the carrier signal changes with respect to message or modulating signal Pulse modulation Angle modulation Amplitude modulation Frequency modulation HintAmplitude modulation is the process in which the amplitude of the carrier signal changes with respect to message or modulating signal13). The first wireless communication over short distance discovered by ________ Armstrong Oliver Lodge Goglielmo Marconi Samuel Morse HintThe first wireless communication over a short distance discovered by Oliver Lodge in 1894 Read more about Wireless Communication.14). The envelope detector is __________ Effective for detection of narrow band AM signal Simple Both a and b None of the above 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 ________ Baud rate Bit rate ISI None of the above Hint The number of bits conveyed or processed for unit time is called bit rate16). Who invented super heterodyne receiver? Armstrong Oliver Lodge Goglielmo Marconi Samuel Morse HintThe super heterodyne receiver is discovered by Armstrong in 191817). In ______ modulation the phase of the carrier signal is modulated by the message signal Pulse modulation Phase modulation Amplitude modulation Frequency modulation Hint In phase modulation the phase of the carrier signal is modulated by the message signal, it is one type of angle modulation18). Who invented first frequency modulation demodulation? Armstrong Oliver Lodge Goglielmo Marconi Samuel Morse HintThe first frequency modulation demodulation scheme is invented by Armstrong in 199319). In ______ modulation the frequency of the carrier signal is modulated by the message signal Pulse modulation Phase modulation Amplitude modulation Frequency modulation HintIn frequency modulation, the frequency of the carrier signal is modulated by the message signal20). Who did PCM encoding of speech signal for digital transmission? Alec Reeves Oliver Lodge Goglielmo Marconi Samuel Morse HintThe PCM encoding of speech signal for digital transmission is done by Alec Reeves in 193721). _________ noise is a static kind of noise which is generated due to electric disturbances Atmospheric noise Extraterrestrial noise Industrial noise Shot noise 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 channel22). The industrial noise occurs in the range around ________ 300MHz-600MHz 1MHz-600MHz 200MHz-600MHz None of the above HintThe industrial noise is basically a manmade noise, it occurs in the range around 1MHz-600MHz23). The area over which cosmic noise effects most is around ______ 10MHz-100MHz 20MHz-120MHz 20MHz-150MHz 30MHz-120MHz HintThe area over which cosmic noise effects is around 20MHz-120MHz in a communication channel24). What are the external noise? Atmospheric noise Extraterrestrial noise Industrial noise All of the above 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 noises25). The double side band suppressed carrier comes under _____ modulation Frequency modulation Analog pulse modulation Amplitude modulation Digital pulse 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 ________ 0-20 KHz 10-20 KHz 5-10 KHz 0-20 MHz HintIn baseband signal, the audio frequency signal range is around 0-20 kHz 27). What are the noises comes under internal noise _____ Atmospheric noise, extraterrestrial noise Resistor, shot, and transient noise Industrial, miscellaneous noise None of the above HintThe resistor noise, shot noise, and transient noises are comes under internal noise28). In synchronous detector _______ errors are generated Phase type error Frequency type error Both a and b None of the above Hint In a synchronous detector both phase and frequency type errors generated because of the synchronization of the local oscillator29). ___________ type of errors are generated in envelope detector Phase type error - Negative clipping Diagonal envelope Both b and c 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 LPF30). The complexity is _________ in synchronous detection High Low Medium Simple HintThe complexity is high in synchronous detector because the phase lock loop, local oscillator, synchronization, and so many things are requiredAnalog Communication Important MCQ’s31). In base band signal the frequency range of amplitude modulation is around ________ 550KHz-1650KHz 500KHz-1600KHz 520 KHz-1620KHz 400 KHz-1650KHz HintIn baseband signal, the frequency range of amplitude modulation is around 550KHz-1650KHz32). In envelope detection the complexity is ____________ High Low Medium Simple HintThe envelope detector is made by a diode, resistance, and capacitance so it is very simple33). The side band cancellation in filter method is done by using ______ Filter Phase shifter of 90 deg Phase shifter of 180 deg None of the above HintThe sideband cancellation in the filter method is done by using filter34). The frequency range of modulating signal in narrow band frequency modulation is between _________ 30 Hz - 15 KHz 15 Hz - 30 KHz 30 Hz - 3 KHz 3 Hz - 15 KHz 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 Reduces Increases Remains same None of the above 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 reduce36). How much is the frequency band in GSM? 500 MHz 600 MHz 700 MHz 900 MHz HintThe frequency band in GSM is around 900 MHz37). In base band signal the video frequency signal range is around ________ 0-50MHz 0-55MHz 0-60MHz 10-55MHz HintIn baseband signal, the video frequency signal range is from 0-55MHz38). In pass band signal, the frequency range of frequency modulation is around _________ 88 MHz-100MHz 88 MHz-110MHz 88 MHz-200MHz 88 MHz-101MHz HintIn passband signal, the frequency range of frequency modulation is around 88 MHz-100MHz39). The frequency band range of Code Division Multiplexing Access in pass band signal is around _______ 1500MHz 1600MHz 1700MHz 1800MHz HintThe frequency band range of Code Division Multiplexing Access in passband signal is around 1800MHz40). In medium modulating index the modulation index is ________ Less than one One to ten Greater than ten Between 1 to 10 HintIn medium modulating index, the modulation index is between one to ten41). The side band cancellation in phase shift method is done by using ______ Selectivity Fidelity Sensitivity All of the above 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 distortion43). In super heterodyne receiver, at high frequency the ______ Bandwidth is low Signal processing should be done Signal transmission should be done Both b and c HintIn the superheterodyne receiver, at high frequency, processing and transmission of the signal should be done, and the bandwidth is low44). The maximum deviation in narrow band frequency modulation is around _________ 5 MHz 5 KHz 7 MHz 9 MHz HintThe maximum deviation in narrow-band frequency modulation is around 5 kHz45). When several signals are multiplexed in a frequency domain then the modulation is called ________ Frequency Division Multiplexing Time Division Multiplexing Code Division Multiplexing Space Division Multiplexing 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 Less than input SNR Greater than input SNR Greater than or equal to input SNR Less than or equal to SNR input 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 ratio47). The levels in differential pulse code modulation are ______ More Depends on number of bits Less None of the above HintThe levels in DPCM are less than the pulse code modulation because the number of bits in DPCM is less than the PCM48). _______ quantizer minimizes the quantization error Uniform quantizer Non-Uniform quantizer LLOYD-Max quantizer None of the above HintThe LLOYD-Max quantizer is an optimal quantizer that minimizes the quantization error49). The quantization error can be defined as _______ q=Q(m)+m q=Q(m)-m q=Q(m)/m None of the above 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 value50). What are the advantages of the angle modulation over amplitude modulation? Noise reduction Improved system fidelity Efficient use of power All of the above 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? Radio broadcasting TV sound transmission Cellular radio All of the above HintRadio broadcasting, tv sound transmission, cellular radio, etc are some applications of Angle modulation 52). How many categories does the modulation index have? One Two Three Four HintThe modulation index is divided into three categories they are high, low, and medium modulation index53). In lower modulating index the modulation index is ________ Less than one One to ten Greater than ten None of the above HintIn lower modulating index the modulation index is less than one54). In a higher modulating index the modulation index is ________ Less than one One to ten Greater than ten None of the above HintIn a higher modulating index the modulation index is greater than ten55). When several signals are multiplexed in a time domain then the modulation is called ________ Frequency Division Multiplexing Time Division Multiplexing Code Division Multiplexing Space Division Multiplexing 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? Resistor noise Transient noise Shot noise All of the above HintThe internal noise is the noises that are generated inside the receiver or an amplifier, the resistor, shot, and transient noise are the internal noises57). The SNR in delta modulation is ______ Fair Poor Good None of the above 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 __________ Quantization level Uniform quantization Non-uniform quantization None of the above HintThe quantization is a many to one mapping, in which all sample values in a particular interval are mapped to a quantization level59). In _________ modulation, frequency or phase of carrier signal changes with respect to modulating signal Frequency Modulation Amplitude Modulation Delta Modulation Angle modulation HintIn angle modulation, frequency or phase of carrier signal changes with respect to modulating signal60). The maximum deviation in wideband frequency modulation is around _________ 75 MHz 75 kHz 70 MHz 90 MHz HintThe maximum deviation in wideband frequency modulation is around 75 kHzAnalog Communication MCQ’s for Interviews61). The frequency range of modulating signal in wideband frequency modulation is between _________ 30 Hz - 15 kHz 15 Hz - 30 kHz 30 Hz - 10 kHz 3 Hz - 15 kHz 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 Frequency is high Frequency is low Applicable for any frequency None of the above 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 filter63). The bandwidth for transmission in pulse code modulation is __________ Higher than the DPCM Lower than the DPCM Equal to DPCM None of the above 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 DPCM64). The formula of amplifier is given by ___________ F+1/F 2F-1/F F-1/F None of the above 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 Less than input SNR Greater than input SNR Greater than or equal to input SNR Less than or equal to SNR input 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 ratio66)________ is a differential modulation Frequency Modulation Amplitude Modulation Delta Modulation None of the above 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 _______ Requires infinite power Requires finite power Doesn’t require power None of the above 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 unrealizable68). The thermal noise _______ Requires infinite power Requires finite power Doesn’t require power None of the above Hint The thermal noise requires finite power69). The number of bits in DPCM is _______ Greater than PCM Less than PCM Equal to PCM None of the above 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 samples70). The levels in PCM are ______ More Depends on the number of bits Less None of the above HintThe levels in PCM depend on the number of bits, if the number of bits is more than the levels are more71). In which case the step size is not fixed? Pulse Code Modulation Delta Modulation Differential Pulse Code Modulation Adaptive Delta Modulation 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 __________ Higher than the PCM Lower than the PCM Equal to PCM None of the above 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 PCM73). When positive changes are happening to AF voltage the junction capacitance will actually _______ in varactor diode modulator Reduces Increases Remains the same None of the above 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 ________ Depends upon the levels Doesn’t depend upon the levels Depends upon the step size None of the above HintThe quantization error in PCM is present depends upon the levels, if the number of levels is more the quantization error will be less75). The SNR in PCM is ______ Fair Poor Good None of the above HintThe SNR in pulse code modulation is good because the signal power is good and it is less affected by noise76). In a uniform quantizer with an even number of quantization levels, the quantizer characteristics arise from __________ –Δ to +Δ –Δ/2 to +Δ/2 –Δ/4 to +Δ/4 None of the above 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 quantizer77). The SNR in adaptive delta modulation is ______ Fair Poor Good Better than DM HintThe SNR in adaptive delta modulation is better than DM because the variable step size is used in ADM so it is better than DM78). The quantization error in DPCM is ________ Quantization is present Quantization is not present Quantization is present but less than PCM None of the above 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. Continuous Discontinuous Both a and b None of the above HintAnalog communication uses a continuous type of signals.80). In which technique data is transmitted using continuous signals? Analog communication Digital communication Both a and b None of the above 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. Variable signal Invariable signal Both a and b None of the above 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? Analog communication Digital communication Both a and b None of the above 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? Photocopiers Audio tapes Emails Both a and b HintAnalog communication technology includes photocopiers, audiotapes, old-landlines, etc.84). Which of the following are the examples of digital communication technology? Photocopiers Audio tapes Emails Both a and b HintDigital communication technology includes emails, wikis.85). Digital communication is represented in ______ form. 0’s 1’s Both a and b Option an alone 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. Time domain Frequency domain Both a and b None of the above 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? Has noise Free from noise Has maximum amplitude Has the maximum frequency 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 _______. Reduces signal to noise ratio Increases signal to noise ratio Improves signals amplitude None of the above 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. 4 5 6 3 HintAnalog contains 6 major components namely, Information source, Input transducer, transmitter, receiver, destination.90). What is the function of an information source? Information is generated Information is sent Information is received Information is read HintInformation source is an input building block of analog communication, where its function is to generate information.Analog Communication Important MCQ’s with Hints91). Messages generated in an input source block of analog communication can be in which form? Words, group of words Symbols Signals All the above 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? Converts energy from one form to another Converts signals Converts domains 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. Nonelectrical, electrical Electrical, nonelectrical Electrical, electrical Nonelectrical, nonelectrical 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? Transmits signal to the receiver Accepts signal from the transducer Accepts input from information source Transmits signal over a channel. HintThe function of the transmitter is to Transmits signals over the channel.95). Which technique is used in the transmitter? Modulation Demodulation Both a and b None of the above 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? It transmits a message from the transmitter to the receiver It listens to message It holds a message All the above 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? Two One Three Four 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? Point to point Broadcast channel Narrowband channel Wideband channel Both a and b HintPoint to point channel and broadcast channel are used in analog communication.99). Which of the following are examples of point to point channel? Wire lines Microwave links Optical fibers All the above 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? It handles several incoming messages from a transmitter It holds single information It listens to channel None of the above HintThe broadcast channel handles several incoming messages from a transmitter.101). What is the functionality of the receiver? It produces an electric message from the received signal in a distorted form It receives the input from the channel Both a and b None of the above 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? Modulation Demodulation Both a and b None of the above HintDemodulation is performed at the receiver.103). What is the functionality of the destination? Converts electrical signal into the original input Converts original input to electrical form Receives input from the receiver It is the final stage of analog communication Option a, b ,d are considered 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. Repetitive Nonrepetitive Alternative None of the above HintA periodic signal is of a repetitive pattern with respect to time.105). An aperiodic signal is of _______ pattern with to time. Repetitive Nonrepetitive Alternative None of the above 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? Message gets altered Message remains same Message is not transmitted None of the above 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. Short frequency High frequency Low frequency Big frequency HintA high-frequency signal can carry a message over a long distance.108). A high frequency signal is also called as ______ signal. Carrier signal UV signal Radio signal None of the above 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? Yes No Maybe 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? Carrier signal Modulated signal Modulating or message signal All the above 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? Continuous wave modulation Pulse modulation Both a and b None of the above 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? Amplitude modulation Angle modulation Analog modulation Digital modulation Both a and b 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? Pulse amplitude modulation Pulse width modulation Phase modulation Frequency modulation Both c and d 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? Analog modulation Frequency modulation Digital modulation Both a and c HintPulse modulation is classified into two types namely, analog modulation and digital modulation.115). Which of the following is an analog modulation? Pulse type amplitude modulation PAM Pulse type width modulation PWM Pulse type position modulation PPM All the above 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? Pulse code modulation Delta modulation Frequency modulation Both a and b 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? One Two Three Four 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? AM type modulator two in number A Local oscillator Summer All the above 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? 2 3 4 5 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 ________. Product type modulators Adder modulator Summer modulator None of the above HintDSBSC modulators are also called product type modulators.121). Pulse modulation is _______ sequence pf rectangular pulse. Periodic sequence Aperiodic sequence Nonrepetitive sequence Both b and c HintPulse modulation is a periodic sequence.122). Which of the following statement is true for pulse amplitude modulation PAM? The pulse amplitude is varied with respect to instantaneous values of baseband modulating signal The pulse width is varied with respect to instantaneous values of baseband modulating signal The pulse position is varied with respect to instantaneous values of baseband modulating signal The pulse duration is varied with respect to instantaneous values of baseband modulating signal 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? The pulse amplitude is varied with respect to instantaneous values of baseband modulating signal The pulse width is varied with respect to instantaneous values of baseband modulating signal The pulse position is varied with respect to instantaneous values of baseband modulating signal The pulse duration is varied with respect to instantaneous values of baseband modulating signal 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? The pulse amplitude is varied with respect to instantaneous values of baseband modulating signal The pulse width is varied with respect to instantaneous values of baseband modulating signal The pulse position is varied with respect to instantaneous values of baseband modulating signal The pulse duration is varied with respect to instantaneous values of baseband modulating signal 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 ________. m(t)= Amcos(2πfmt) M (t) = A cos (2π fm t) M(t) = A cos (2π f t) m (t) = Am cos (2π f t) 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 ________. c (t) = Ac cos ( 2π fc t) c (t) = Ac cos ( 2π t) c (t) = Ac cos ( π fc t) C (t) = Ac cos ( 2π fc t) 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? µ = Am / Ac µ = Ac / Am µ = Am µ = Ac 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? µ = 1 µ = 0 µ < 1 µ > 1 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? One Two Three Four 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 ________. Amplitude Bandwidth Frequency Time period HintIf the maximum frequency is subtracted from the lower frequency it is called bandwidth.131). What is the bandwidth of AM wave? BW = 2fm BW = fm BW = 2 BW = 3 HintThe bandwidth of AM wave is BW = 2fm.132). Which type of modulators are used in AM wave generation? Square law modulator Switching modulator Triangular modulator Both a and b HintSquare law modulator and switching modulator are used in AM wave generation.133). Which of the following are the components of square law modulator? Summer Square law device Bandpass filter All the above 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? Summer Switching diode Bandpass filter All the above 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 _______. Modulation Demodulation Encryption Decryption HintThe process of extracting the original message from the signal is called demodulation.136). Demodulation is done at ______ side. Transmitter Receiver Channel Both a and b HintDemodulation is done at the receiver side.137). What is the functionality of the envelope detector? It detects AM wave with high frequency It detects FM wave high frequency It detects PM wave high frequency None of the above HintThe functionality of the envelope detector is to detect AM waves with high frequency. Time is Up! Time's up
