Frequently Asked Questions -Analog Communication

Please check the following links,which consists of  Unit wise FAQ in Analog Communication.

AC UNIT-1- Important Questions OR FAQ

AC UNIT-2- Important Questions OR FAQ

AC UNIT-3-Important Questions OR FAQ

AC UNIT-5-Important Questions OR FAQ

Basic Electronics Lab Viva Questions

Experiment wise viva questions Basic Electronics Lab

PN-Junction Diode:

  1. What is a diode?
  2. What are the applications of diode?
  3. Draw the symbol of PN junction diode and mark anode and cathode.
  4. Define threshold voltage or cut in voltage of a diode.
  5. define dynamic and static resistances of a diode.
  6. Cut-in voltage of Si diode is…………………
  7. Cut-in voltage of Ge diode is…………………
  8. Draw the VI characteristics of PN junction diode.
  9. What is forward bias of a junction diode? Explain with circuit diagram.
  10. What is reverse bias of a junction diode? Explain with circuit diagram.
  11. Define space charge or Depleted region of a diode?
  12. Explain the working operation of a junction diode in forward and reverse bias.
  13. p type material means………….. Give some examples of N-type materials
  14. n type material means…………Give some examples of P-type materials
  15. Ideal diode acts as short circuit under forward bias. Or draw the equivalent circuit of ideal diode in forward bias.
  16. Ideal diode acts as open circuit under reverse bias. Or draw the equivalent circuit of ideal diode in reverse bias.
  17. Draw the equivalent circuit of practical diode in forward bias and reverse bias.
  18. What are the differences between avalanche and Zener break down.
  19. What are intrinsic and extrinsic impurities?
  20. Differentiate a conductor, semiconductor and dielectric material.
  21. Write the diode current equation.

 Zener Diode:

  1. What is Zener diode? Define how it is different from ordinary PN diode.
  2. What are the applications of Zener diode?
  3. Draw the symbol of Zener diode and mark anode and cathode.
  4. Define Zener breakdown.
  5. What is the Zener breakdown voltage value———–.
  6. How Zener diode is acting as a voltage regulator?
  7. What is the cut-in voltage of a Zener diode————.
  8. Draw the equivalent circuit of Zener diode?
  9. Zener diode operates in reverse bias? Why?
  10. Explain avalanche multiplication in detail.
  11. Explain Zener multiplication in detail.
  12. Give two differences between avalanche and Zener multiplication.

Half Wave rectifier and Full wave Rectifier (same questions are valid for FWR)

  1. What is a rectifier? How diode is used as a rectifier?
  2. Define ripple factor?
  3. What is the need for filter at the output of a rectifier?
  4. What is percentage of regulation?
  5. Give the ripple factor values for HWR and FWR (read comparison table between HWR and FWR).
  6. What is the efficiency of HWR and FWR? Give values.
  7. What are the advantages of FWR over HWR?
  8. What are the disadvantages of HWR?
  9. What are the drawbacks of FWR?
  10. Define PIV of a diode.
  11. PIV of HWR and FWR are………..
  12. why we need rectifiers?
  13. where we use rectifiers ?
  14. what are the differences between rectifier and converter?

CE/CB characteristics:

  1. Draw the symbol of transistor.
  2. Draw pnp and npn transistor symbols.
  3. What are three configurations of a BJT?
  4. Draw the circuits of CE, CB and CC configurations.
  5. What is CE or Grounded Emitter configuration?
  6. What is CB or Grounded Base configuration?
  7. What is CC or Grounded Collector configuration?
  8. What are input and output characteristics of BJT?
  9. Draw input and output characteristics of CE configuration.
  10. Draw input and output characteristics of CB configuration.
  11. What are the applications of CE and CB transistors?
  12. Comparison table of CE, CB and CC configurations in terms of input resistance, output resistance, voltage gain, current gain and applications.
  13. What are the three terminals of a transistor?
  14. Define doping levels of emitter, base and collector.
  15. Define early effect in CB transistor.
  16. The majority carriers in pnp transistor are………..
  17. The majority carriers in npn transistor are………..
  18. Why BJT is called as bipolar device?
  19. Is BJT a uni polar or bipolar device?
  20. What are the applications of transistors?
  21. what is the phase difference between input and output waveforms of CE transistor( ans: 180o)
  22. What is the phase difference between input and output waveforms of CB transistor ( ans: 0o or 360o).
  23. Why NPN transistor is preferred over PNP transistor?
  24. Why CE is preferred over other combinations in voltage amplifiers?
  25. Define saturation, cutoff, active regions of a transistor?
  26. What is cutoff region of operation of a transistor?
  27. Read about comparison tables of Si, Ge transistors for active cutoff and cutin and saturation voltages.

JFET:

  1. What is FET or JFET?
  2. What are the differences between BJT and FET?
  3. Why BJT is called as Current controlled device?
  4. Why FET is called as Voltage controlled device?
  5. Draw the symbol of FET?
  6. Symbols of N-channel and p channel FETs.
  7. Differences between N- channel and P- channel FET’s?
  8. Draw the input or output characteristics of JFET?
  9. What are the meanings of source drain and gate?
  10. What are the applications of FET?
  11. What are the advantages of FET over BJT?
  12. Draw h-parameter model of a BJT in CE/CB configurations?
  13. Define pinchoff voltage of a FET?
  14. Explain about linear saturation and breakdown regions of CE/CB output characteristics?
  15. Explain about linear saturation and breakdown regions from drain or output characteristics of JFET
  16. Define 4 h-parameters of BJT in CE configuration?
  17. Draw the equivalent circuit of FET?
  18. define µ, g , rd in FET? what is the relation between those three parameters?
  19. define trans conductance and drain resistance of FET?
  20. The input resistance of a JFET is very high in Mega ohms.
  21. Working of JFET.
  22. Applications of JFET.

 

Operational Amplifier:

 

  1. What is Operational Amplifier?
  2. What are the ideal characteristics of Op-amp?
  3. What are the applications of op-amp?
  4. What is inverting amplifier?
  5. What is non inverting amplifier?
  6. What is meant by open loop and closed loop op-amp?
  7. Identify the feedback resistor in inverting and non inverting amplifiers (ans:Rf).
  8. What are the advantages of op-amp over feedback amplifiers?
  9. Define slew rate?
  10. Draw circuits of integrator and differentiator using op-amp
  11. Draw adder and subtractor circuits using op-amp.
  12. What is virtual ground in op-amp circuits?
  13. What is open loop gain of an ideal op amp?

Oscillators:

RC Phase Shift Oscillator:

  1. Mention the two conditions required for oscillations in RC phase shift oscillator?
  2. Give the formula for frequency of oscillations in RC phase shift oscillator?
  3. The phase produced by a single RC network is RC phase shift oscillator?
  4. RC phase shift oscillator uses positive feedback or negative feedback?
  5. The phase produced by basic amplifier circuit in RC phase shift oscillator is?
  6. What is the difference between damped oscillations and un damped oscillations?
  7. What are the applications of RC phase shift oscillator?
  8. How many resistors and capacitors are used in RC phase shift feedback network?
  9. How the Barkhausen’s criterion is satisfied in RC phase shift oscillator
  10. Mention the basic reason for any oscillations?
  11. What is meant by Barkhausen’s criterion?
  12. Audio frequency range is————
  13. RC phase shift oscillator is ——–
  14. Oscillator is a circuit operates on internal input power supply yes or no?
  15. Define an oscillator?
  16. Oscillator did not take any external input yes or no?
  17. Type of feedback used in oscillators is——-
  18. Radio frequency range is———–
  19. Show that single RC section provides a phase shift of 60 degrees.
  20. Positive feedback causes instability yes or no?
  21. In oscillators loop gain must be————–
  22. In oscillators the overall phase shift produced by the circuit is————
  23. Feedback gain 𝛽 must be less than———–

 COLPITTS AND HARTLEY’S OSCILLATORS:

  1. What are the advantages of hartley’s and colpitts oscillators over RC phase shift oscillator?
  2. Applications of Colpitts and Hartleys oscillators are—–.
  3. Colpitts oscr uses ———- in its feedback network.
  4. Hartleys oscr uses ———–in its feedback network.
  5. Define mutual inductance—–
  6. colpitts and hartleys ocsillators are used at ———— frequencies.
  7. Give the formula for frequency of oscillations in Colpitts oscillator.
  8. Give the formula for frequency of oscillations in Hartley’s oscillator?

SINGLE STAGE CE AMPLIFIER:

  1. What is the phase difference between input and output waveforms of a CE amplifier?
  2. What type of biasing is used in the given circuit?
  3. What is the effect of emitter bypass capacitor on frequency response of a CE amplifier?
  4. What is the effect or importance of coupling capacitor?
  5. Why source resistance Rs is used in the input side?
  6. What are the different regions of operation of a BJT?
  7. The phase difference of input and output in CB amplifier?
  8. CE amplifier is voltage or current amplifier?
  9. Draw the equivalent h-parameter model of a CE amplifier?
  10. Why NPN transistor is preferred over PNP transistor?
  11. What is the effect of bypass capacitor over stability of the CE amplifier?
  12. The CE amplifier is in voltage divider bias or in fixed bias configuration?
  13. The values of hfe,hie,hoe and hre in CE configuration are—————-.
  14. hfe,hie,hoe and hre are called as——————–.
  15. What do you mean by loading effect?
  16. What are the practical applications of single stage CE amplifier?
  17. How do you know the amplifier is single stage CE amplifier?
  18. Why this circuit is called RC coupled amplifier?
  19. What is the operating point in CE amplifier from the design specifications?
  20. Quiescent conditions means——–
  21. D.C conditions are for———
  22. What is the relationship between collector current and base current?
  23. Does β and hfe are one and the same?
  24. Why coupling capacitor Cb is connected in reverse (-,+) at the input side and Cc is connected in forward(+,-) at the output side?
  25. How do u know a transistor is working in cut off region?
  26. Write VBE(active),VBE(sat),VBE(cutoff) values of a Si and Ge transistors
  27. Transistor meaning is———
  28. Define frequency response of a CE amplifier?
  29. Define voltage gain of a CE amplifier?
  30. Units of gain as a ratio are———-
  31. Units of gain in logarithim is———
  32. Magnitude response and frequency response are one and the same say yes or no?
  33. Define bandwidth?
  34. What are 3 dB frequencies?
  35. Define cutoff frequencies?
  36. BW is approximately equal to fH justify?
  37. Gain is constant in————-
  38. Semi logarithmic graph is linear or non linear graph?
  39. Stability factor is a function of—–
  40. In the circuit R1 and R2 are used for——–
  41. The feedback type that Re and Ce introduces in the circuit is———–(Ans: negative feedback).
  42. Negative feedback increases stability yes or no(Ans:yes).
  43. CB amplifier provides more band width than CE amplifier justify?

 

Note: Read advantages and disadvantages and applications of every experiment.

 ALL THE BEST 

 Prepared by   P.Lakshmi Prasanna

 

 

 

 

 

 

 

 

 

 

Computer Networks Routing Algorithms

ROUTING ALGORITHMS

Routing Algorithm:- The Algorithm that manages the Routing Tables and makes the Routing Decisions is called Routing Algorithm.

Implementation of Connection – Oriented Network layer Service:-

  • In this service the subnet is called Virtual Circuit Subnet.
  • A path from Source Router to Destination Router is established before sending any packets. That Router is used for all traffic flowing over that connection.

Ex:- A Telephone System.

  • When connection is released, the virtual circuit is also terminated.

Let us see an example, The figure shows the routing using Virtual Circuit subnet, In this Host H1 wants to send packets to H2

lp

 

lop

Now H1 will establishes a connection1 with Host H2 whenever packet comes from host H1 , we use connection 1 with identifier as 1. i.e, from routing table of A , a packet is coming from H1 , identifier is 1 then use the outgoing router C with identifier 1 .

Similarly for H3 use identifier as 2. This is called as lablel Switching .

The comparison between these connection oriented and connection less services or Virttual circuit or data gram subnets is given in the table.

 

Electronics Circuits Lab Viva questions

ELECTRONIC CIRCUITS LAB VIVA QUESTIONS

 CLIPPERS:

  1. What are the applications of clippers?
  2. Diode cut in voltage value for si and Ge diodes?
  3. Why the output of the clipper is taken in d.c mode?
  4. Other names of clippers are—— –.
  5. Voice frequency range is——– –.
  6. Positive peak clipper means
  7. Negative peak clipper means
  8. Positive base and negative base clippers means
  9. What is the difference between clipping and clamping operations?
  10. And the working procedures of each clipping circuit
  11. How clippers are applicable in noise reduction in audio applications?
  12. Draw the output waveforms of different clippers with different input and reference voltages—–
  13. Why clippers are called as diode clippers?
  14. What is the difference between slicing and clipping of a voltage waveform?
  15. Clippers comes under linear or non linear wave shaping?
  16. Explain linear and nonlinear wave shaping meanings?
  17. Names some linear and non linear wave shaping circuits?
  18. Define diode threshold and cutin voltages?
  19. An ideal diode acts as———– under forward
  20. An ideal diode acts as———— under reverse
  21. Practical diode equivalent circuit in forward bias——–
  22. Practical diode equivalent circuit in reverse bias——–
  23. Draw diode d.c characteristics.

CLAMPERS:

  1.  Define clamping operation? And how it is different from clippers?
  2. What are the other names of clampers?
  3. Difference between clipping and clamping circuits
  4. Why capacitors are used in clampers?
  5. What are different types of clampers?
  6. Working Operation of each clamper circuit
  7. Practical applications of clampers are
  8. What happens in the output waveform if the polarity of capacitor is changed in the clampers
  9. Capacitor acts as———- for D.C input
  10. Capacitor acts as————- for A.C
  11. Fully charged capacitor acts as——– –.
  12. What do u mean by transient and steady state response of a clamper?
  13. DC restorers are used in CRO’s yes or no
  14. DC inserter means————
  15. Voltage or amplitude slicers means———–
  16. Voltage or amplitude limiters means———– –.
  17. Explain the operation of positive peak clamper?
  18. What is the working principle of a capacitor/
  19. Output waveforms of clampers with different input and different reference voltages—
  20. The voltage across a capacitor remains———— once the capacitor is fully

SINGLE STAGE CE AMPLIFIER:

  1. What is the phase difference between input and output wave forms of a CE amplifier?
  2. What type of biasing is used in the given circuit?
  3. What is the effect of emitter bypass capacitor on frequency response of a CE amplifier?
  4. What is the effect or importance of coupling capacitor?
  5. Why source resistance Rs is used in the input side?
  6. What are the different regions of operation of a BJT?
  7. The phase difference of input and output in CB amplifier?
  8. CE amplifier is voltage or current amplifier?
  9. Draw the equivalent h-parameter model of a CE amplifier?
  10. Why NPN transistor is preferred over PNP transistor?
  11. What is the effect of bypass capacitor over stability of the CE amplifier?
  12. The CE amplifier is in voltage divider bias or in fixed bias configuration?
  13. The values of hfe,hie,hoe and hre in CE configuration are———– –.
  14. hfe,hie,hoe and hre are called as————— –.
  15. What do you mean by loading effect?
  16. What are the practical applications of single stage CE amplifier?
  17. How do you know the amplifier is single stage CE amplifier?
  18. Why this circuit is called RC coupled amplifier?
  19. What is the operating point in CE amplifier from the design specifications?
  20. Quiescent conditions means——–
  21. C conditions are for———
  22. What is the relationship between collector current and base current?
  23. Does β and hfe are one and the same?
  24. Why coupling capacitor Cb is connected in reverse (-,+) at the input side and    Cc is connected in forward(+,-) at the output side?
  25. How do u know a transistor is working in cut off region?
  26. Write VBE(active),VBE(sat),VBE(cutoff) values of a Si and Ge transistors
  27. Transistor meaning is———
  28. Define frequency response of a CE amplifier?
  29. Define voltage gain of a CE amplifier?
  30. Units of gain as a ratio are———-
  31. Units of gain in logarithim is———
  32. Magnitude response and frequency response are one and the same say yes or no?
  33. Define bandwidth ?
  34. What are 3 dB frequencies?
  35. Define cutoff frequencies?
  36. BW is approximately equal to fH justify?
  37. Gain is constant in————-
  38. Semi logarithmic graph is linear or non linear graph?
  39. Stability factor is a function of—–
  40. In the circuit R1 and R2 are used for——–
  41. The feedback type that Re and Ce introduces in the circuit is———–(Ans: negativefeedback).
  42. Negative feedback increases stability yes or no(Ans:yes).
  43. CB amplifier provides more band width than CE amplifier justify?

TWO STAGE RC COUPLED CE AMPLIFIER:

  1. What is the need for cascading in amplifiers?
  2. Why do we need two stage CE amplifier?
  3. Why this circuit is called two stage CE amplifier?
  4. What is the relationship between gain and bandwidth?
  5. Cascading of number of stages in amplifiers increases——— –.
  6. Cascading of number of stages linear amplifiers decreases—– –.
  7. Why do we use a coupling capacitor between two stages?
  8. Why RC coupling is preferred in Audio frequency range?
  9. Explain various types of capacitors?
  10. What do you mean by loading effect? How to avoid it?
  11. Identify the stages of the amplifier?
  12. CE-CE combination is called as———-
  13. Cascade configuration means——
  14. What is the overall gain of two satge amplifier—–
  15. Is two stage amplifier is a multistage amplifier or not?
  16. Why this circuit is called RC coupled amplifier?
  17. Does CB-CB combination is possible?
  18. CE-CC combination is known as——-
  19. CB-CC combination is called as——–
  20. There exist an inverse proportionality between gain and BW yes or no?

VOLTAGE SERIES FEEDBACK AMPLIFIERS:

  1. What do u mean by feedback?
  2. What are the two types of feedback?
  3. What are the advantages of negative feedback over positive feedback?
  4. Voltage series feedback means?
  5. Input of a voltage series combination is———–
  6. Output of a voltage series combination is———–
  7. For voltage series amplifier Ri , Ro,gain and BW changes as——-
  8. How does u know the feedback is voltage series in the given circuit?
  9. What are different types of feedback topologies?
  10. Applications of voltage series amplifier?
  11. What is the difference between two stage and voltage series amplifier?
  12. Which is the best topology among four?
  13. How feedback amplifiers are different from ordinary amplifiers?
  14. Define feedback gain?

RC PHASE SHIFT OSCILLATOR:

  1.  Mention the conditions for oscillations in RC phase shift oscillator?
  2. Give the formula for frequency of oscillations in RC phase shift oscillator?
  3. The phase produced by a single RC network is RC phase shift oscillator?
  4. RC phase shift oscillator uses positive feedback or negative feedback?
  5. The phase produced by basic amplifier circuit in RC phase shift oscillator is?
  6. What is the difference between damped oscillations un damped oscillations?
  7. What are the applications of RC phase shift oscillator?
  8. How many resistors and capacitors are used in RC phase shift feedback network?
  9. How the Barkhausen’s criterion is satisfied in RC phase shift oscillator
  10. Mention the basic reason for any oscillations?
  11. What is meant by Barkhausen’s criterion?
  12. Audio frequency range is————
  13. RC phase shift oscillator is ——–
  14. Oscillator is a circuit operates on internal input power supply yes or no?
  15. Define an oscillator?
  16. Oscillator did not take any external input yes or no?
  17. Type of feedback used in oscillators is——-
  18. Radio frequency range is———–
  19. Show that single RC section provides a phase shift of 60
  20. Positive feedback causes instability yes or no?
  21. In oscillators loop gain must be————–
  22. In oscillators And overall phase shift produced by the circuit is————
  23. Feedback gain 𝛽 must be less than———–

COLPITTS AND HARTLEY’S OSCILLATORS:

  1. What are the advantages of hartley’s and colpitts oscillators over RC phase shift oscillator?
  2. Applications of C and H oscillators are—–.
  3. C oscillator uses—- as feedback network.
  4. H oscillator uses—– as feedback
  5. Define mutual inductance—–
  6. These are used at———–

MEASUREMENT OF IMPEDANCES:

  1. Differentiate symmetrical and asymmetrical networks?
  2. Define image impedance?
  3. Define characteristic or nominal impedance?
  4. Theoretical Calculations of open circuit and short circuit impedances for all the
  5. What is the significance of image impedance?
  6. Is there any difference between image and inverse impedance?
  7. Why char impedance is called as nominal impedance?
  8. Does char impedance and image impedance are same yes or no?

CONSTANT –K-LOW PASS FILTER:

  1. Define a filter?
  2. What is the difference between ordinary LPF and constant –k-LPF?
  3. Why this filter is called as constant-k-low pass filter?
  4. What does u mean by a LPF?
  5. Draw the gain characteristics of ideal and practical Low pass filters?
  6. Define attenuation? units of attenuation are——
  7. Gain and attenuation are——-
  8. Define cut off frequency of a constant k low pass filter?
  9. Draw the attenuation characteristic and explain that graph?
  10. Draw the output voltage vs frequency curve and explain it?’
  11. What are the applications of constant-k low pass filter?
  12. Advantages and disadvantages of constant k low pass filter?

M-DERIVED HIGH PASS FILTER:

  1. Define high pass filter?
  2. Define the constant m?
  3. How m derived filter is different from ordinary HPF?
  4. Why we will go for m derived filters?
  5. Draw the model graphs of m derived HPF and explain?
  6. Applications of m derived HPF?
  7. Advantages and disadvantages of m derived HPF?
  8. Define infinity frequency and cut off frequency?
  9. Are these filters are passive filters or active filters?

NOTE: read applications and advantages and disadvantages for all the circuits.

analog communications lab viva questions

EXPERIMENT WISE VIVA QUESTIONS ANALOG COMMUNICATION LAB

Amplitude Modulation:

  1. What is meant by Modulation? What is the need for modulation?
  2. What are different types of analog modulation techniques?
  3. What are the other names of message signal? What are the other names of carrier signal?
  4. Write the equation of AM signal and explain each parameter in that equation?
  5. Define Amplitude Modulation? Define modulation depth or modulation index?
  6. What is the range of Audio frequency signals? What is the range of Radio frequency signal?
  7. What are the applications of Amplitude modulation?
  8. How many generation methods are there to generate an AM wave? What are the methods of demodulation of an AM wave?
  9. Explain the operation of diode detector circuit?
  10. Write the formula for modulation index? Differentiate under, over and perfect modulation in AM?
  11. As the amplitude of message signal increases, modulation index increases or decreases?
  12. Define single tone modulation? In laboratory type of AM is single tone modulation or not?
  13. Draw the frequency spectrum of AM wave?
  14. If modulation index is 100%, calculate the ratio of total power to carrier power of an AM wave?
  15. If µ=1 in an AM wave what is the amount of power saving in an AM wave? What is the band width of an AM wave?
  16. Explain the operation of AM modulator? Explain the operation of 8038 circuit in AM modulator?
  17. Explain the procedure of Amplitude modulation? What is the significance of Emax and Emin points in AM wave?
  18. Plot message, carrier and AM signals?
  19. What is meant by envelope detector?
  20. The frequency of AM wave follows — (message signal frequency or carrier frequency)?
  21. The amplitude of AM wave at fc +fm is— and The amplitude of AM wave at fc -fm is—–
  22. In amplitude modulation the amplitude of ——— is changing with respect to ——
  23. Envelope of AM signal follows————– (message signal/ carrier signal)?
  24. What are the advantages and disadvantages of AM?
  25. How demodulated signal differs from original signal in AM?
  26. The two important distortions that can appear in the demodulated output of an envelope detector are————– and—————————- –.
  27. Differentiate high-level and low-level modulations in AM?
  28. What is trapezoidal rule?

Balanced Modulator:

  1. What are the disadvantages of AM?
  2. Most of the power in AM spectrum is carried by ————
  3. Define DSBSC modulation?
  4. How DSBSC is more efficient than AM in terms power saving, explain?
  5. What is meant by frequency response?
  6. Draw the magnitude response or amplitude spectrum of DSBSC signal?
  7. The signal generated by balanced modulator is———–
  8. Draw the wave form of DSBSC wave and AM wave, and differentiate those two waveforms?
  9. Give the equation of DSBSC signal?
  10. What are the generation methods of DSBSC?
  11. What are the demodulation methods of DSBSC?
  12. What is the bandwidth of DSBSC signal?
  13. Define Costas loop and it’s operation?
  14. Amount of power saving in DSBSC signal is————
  15. Coherent detection means?
  16. Give the practical applications of balanced modulator?
  17. Explain the operation of product modulator?
  18. Why the circuit is called balanced modulator?
  19. If the circuit is operating in balanced state, the modulation index value is——- –.
  20. Explain the working procedure of 1496 IC for the generation of DSBSC wave?
  21. As message signal amplitude increases, carrier suppression in dB’s ———
  22. Plot message, carrier and DSBSC waves and explain each wave clearly.
  23. How do you differentiate modulation by demodulation?
  24. Explain the significance of local oscillator frequency in modulators and in
  25. Differentiate synchronous and non synchronous detection techniques in analog modulators?
  26. The phase shift at zero crossings in DSBSC wave is——- –.
  27. What is Quadrature carrier multiplexing?
  28. How DSBSC is different from SSB?

Frequency Modulation:

  1. Define Frequency modulation? How it is different from phase modulation?
  2. Write equation of FM wave, explain each parameter in it?
  3. Draw the amplitude spectrum of FM wave?
  4. Give the Carson’s rule in FM?
  5. Define modulation index β, frequency deviation?
  6. Differentiate Narrow band FM with Wide band FM?
  7. Explain the FM operation using 8308IC?
  8. Draw message, carrier and FM waves and explain each wave clearly?
  9. Explain the methods for generation of FM and its demodulation?
  10. How FM wave is different from PM wave?
  11. Give the practical applications of FM?
  12. State advantages and disadvantages of FM?
  13. The range of speech signals is——— –.
  14. Type of Modulation used in radios is——- –.
  15. Type of modulation used for voice signals in T.V — and for video signals in V is—- –.
  16. Noise immunity is more in which analog modulation technique———– –.
  17. FM is more robust to noise compared to AM, why?
  18. Carson’s rule is for———- –.
  19. In commercial FM broadcasting, the audio frequency range handled is only up to—- –.
  20. The transmission band width required for commercial FM broadcasting is——– –.
  21. Define Hilbert transform?
  22. Explain capture effect in FM broadcasting?

Pre-emphasis and De-emphasis:

  1. Define pre-emphasis and De-emphasis processes in
  2. Why Pre-emphasis is used at Transmitter of FM and de-emphasis at FM receiver?
  3. Draw the pre-emphasis circuit and explain its working in detail?
  4. Draw de-emphasis circuit and explain its working in detail?
  5. Draw the frequency response characteristics of pre-emphasis and de-emphasis explain each one in detail?
  6. Calculate the cut-off frequencies of pre-emphasis and de-emphasis circuits practically
  7. Pre-emphasis circuit operation is similar to——— –.
  8. De-emphasis circuit operation is similar to——— –.
  9. What is the necessity of boosting up high frequencies in frequency modulation communication system?
  10. Define 3dB frequencies?

Sampling and reconstruction:

  1. Define sampling theorem? What is the need for sampling?
  2. What are the necessary and sufficient condition for sampling and reconstruction of a signal?
  3. Define Nyquist rate and Nyquist interval in sampling theorem?
  4. If message frequency is 2 KHz and sampling frequency is 2 KHz,4 KHz, 8 KHz and 16 KHz in each case the number of samples are—————————– –.
  5. What are different types of sampling techniques?
  6. What was the effect on sampled signal if fs < 2 fm ?
  7. Draw the amplitude spectrum of sampled signal if fs < 2 fm, fs =2 fm, fs > 2 fm.
  8. What is aliasing effect in sampling? How to avoid it?
  9. Why do we use pre-filtering in sampling?
  10. What do you mean by reconstruction of sampling theorem?
  11. What are the types of filters used in reconstruction?
  12. Define sample and hold process?
  13. Differentiate second order, fourth order and sixth order low pass filters in reconstruction process.
  14. Explain the sampling and reconstruction process in detail by using the trainer
  15. Define band pass sampling?
  16. How sampling is different from PAM?
  17. Define a continuous time signal or an analog signal. Give some examples of analog signals.
  18. Define a discrete time signal. Give some examples of discrete
  19. What is the difference between discrete and a digital signal?
  20. Define a digital signal? Give some
  21. What is the need for converting a continuous signal into a discrete
  22. Explain about zero-order hold circuit.
  23. How to convert an analog signal into digital signals?

Digital signal processors operates———— as inputs.As the number of samples increases, the reconstruction of original signal becomes?

Pulse Amplitude Modulation:

  1. What is the basic principle of PAM?
  2. Name some Pulse Modulation techniques?
  3. Define PAM?
  4. How PAM is different from AM?
  5. Can we produce a PAM signal using a sampling circuit?
  6. Differentiate PAM output with sampling output?
  7. Does PAM come under Analog modulation technique or Digital Modulation technique?
  8. What is the Bandwidth of PAM?
  9. Compare BW of PAM and AM?
  10. Draw waveforms of PAM. explain each one briefly.
  11. What are the advantages of PAM over AM?
  12. What are the advantages and Disadvantages of PAM?
  13. Explain the working procedure PAM kit?
  14. Can we use PAM technique in TDM?
  15. Differentiate uni-polar and bi-polar PAM.
  16. What do you mean by zero order holding? And draw the circuit diagram of zero-order hold circuits?
  17. What are the drawbacks of PAM?
  18. Explain the working of PAM demodulation circuit?
  19. Define Flat-Top sampling?
  20. Draw the circuit diagram of Flat-Top Sampled circuit?
  21. What was the roll off characteristics of sinc pulse?

    Pulse Width Modulation (PWM):

    1. Define PWM?
    2. Differentiate PWM, PAM and PPM?
    3. Name the applications of Mono-stable multivibrator?
    4. What is a Multivibrator?
    5. Differentiate Monostable, Bi stable and Astable Multivibrators?
    6. How a Monostable Multivibrator produces a PWM signal?
    7. What are the other names of PWM?
    8. Define Pulse Duration Modulation?
    9. What is Pulse Time Modulation?
    10. Draw PAM and PWM signals and each one in detail.
    11. Draw PWM signal with respect to message signal?
    12. In PWM —————- of Pulse carrier signal is changing with respect to message signal.
    13. Explain the operation of PWM circuit.
    14. 555 timer in Monostable mode produces————.
    15. 555 timer in Astable mode produces——————.
    16. What are the advantages of PWM over PAM?
    17. What is the difference between PWM and FM?
    18. Which type of noise is affecting the amplitude of PWM signal?
    19. Which system is more immune to noise (PWM or PAM)?
    20. What are the disadvantages of PWM?
    21. What are the applications of PWM?
    22. Band Width of PWM is—————-.
    23. Band width of PAM is—————-.

      Pulse Position Modulation (PPM):

      1. Define PPM?
      2. The information is conveyed by ————- of Pulses in PPM.
      3. In PWM information is conveyed by————— of pulses.
      4. In PAM information is conveyed by————— of pulses.
      5. What are the advantages and disadvantages of PPM?
      6. Compare PPM with Phase Modulation.
      7. PAM is similar to————————–.
      8. PWM is similar to————————–.
      9. PPM is similar to————————–.
      10. Differentiate Analog Modulation Techniques with Pulse Modulation Techniques.
      11. What are the applications of PPM?
      12. Draw PPM signal with respect to message signal.
      13. Draw PPM signal with respect to PWM signal.
      14. Explain the operation of PPM Modulator?

        Phase Locked Loop (PLL):

        1. What are the applications of PLL?
        2. Why this circuit is called Phase Locked Loop?
        3. What are the three components of PLL circuitry?
        4. Explain the operation of PLL by using a Block Diagram?
        5. Define free-running frequency?
        6. Define Lock range and Capture range of a PLL?
        7. What is meant by Frequency synthesizer?
        8. Why PLL is used in FM Receivers/
        9. How PLL is used in FSK demodulation circuits?
        10. What do you mean by Lock state in a PLL?
        11. What is meant by Pull in time in PLL?
        12. Phase Detector or Phase Comparator is used for ——————.
        13. Why VCO is used in feedback loop of PLL?
        14. What are the input and Output signals of a VCO in a PLL?
        15. What are the advantages and Disadvantages of PLL?
        16. Why Lock range is greater than Capture range in a PLL?

          Time Division Multiplexing (TDM):

          1. Define the concept of Time Division Multiplexing?
          2. Differentiate Multiplexing and Sampling?
          3. What are the different types of Multiplexing Techniques?
          4. Does TDM come under analog Multiplexing or Digital Multiplexing?
          5. Define a frame in a TDM?
          6. Why synchronization is required in TDM?
          7. Why multiplexing is required?
          8. What do you mean by inter-leaving gaps in TDM frame?
          9. If two signals of frequencies 2KHz and 4 KHz are multiplexed in time –domain then draw TDM signal
            1. Without inter-leaving gap.
            2. with inter-leaving gap of 10 ms.
          10. What are the advantages and Disadvantages of TDM?
          11. Differentiate TDM with FDM?
          12. What are the advantages of TDM over FDM?
          13. Explain the operation of TDM using trainer kit used.
          14. Synchronous TDM means?

            Additional Questions:

            1. What is a filter?
            2. Differentiate Active and Passive Filters?
            3. Why LPF is used in Demodulation Circuits?
            4. Why pre-filtering is required in sampling?
            5. Anti-aliasing is achieved by using———– in Sampling Circuits?
            6. Define Single-tone modulation in AM and FM?
            7. Why FM receivers are more immune to AM receivers?
            8. BW of Narrow band FM is ——————.
            9. BW of AM is ———————————-.
            10. How to calculate Image frequency of a Radio Receiver?
            11. Define Power Spectral Density.
            12. Define AWGN noise.
            13. Define SNR.
            14. Where do we use Hilbert Transform?
            15. Over modulation in AM means….
            16. What is µ value when AM wave is similar to DSBSC wave?

           

         

       

     

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