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ADC Imp Questions

This document covers topics in digital and analog communication systems across 5 units: Unit 1 discusses amplitude modulation techniques including double sideband suppressed carrier modulation generated using a balanced modulator or ring modulator. It also covers modulation index and percentage modulation calculations. Unit 2 focuses on frequency modulation including transistor reactance modulation, bandwidth calculations for FM signals, and the use of limiters and preemphasis filters in FM radio. Unit 3 explains superheterodyne receivers including the transistor radio frequency (TRF) receiver. It also covers automatic gain control (AGC) and preemphasis/deemphasis circuits. Unit 4 introduces various pulse modulation techniques including pulse amplitude, width, and position modulation as well as their generation

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Ravindra Vasari
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249 views3 pages

ADC Imp Questions

This document covers topics in digital and analog communication systems across 5 units: Unit 1 discusses amplitude modulation techniques including double sideband suppressed carrier modulation generated using a balanced modulator or ring modulator. It also covers modulation index and percentage modulation calculations. Unit 2 focuses on frequency modulation including transistor reactance modulation, bandwidth calculations for FM signals, and the use of limiters and preemphasis filters in FM radio. Unit 3 explains superheterodyne receivers including the transistor radio frequency (TRF) receiver. It also covers automatic gain control (AGC) and preemphasis/deemphasis circuits. Unit 4 introduces various pulse modulation techniques including pulse amplitude, width, and position modulation as well as their generation

Uploaded by

Ravindra Vasari
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Unit-1

1. Explain the generation of DSB-SC wave using a)balanced modulator b)ring


modulator
2. Describe the detection of AM wave using a)square law detector b)envelope detector
3. Write AM equation. Define modulation index, and percentage modulation
4. A modulating signal consists of a symmetrical triangular wave having zero dc
component and peak to peak voltage of 12V. It is used to amplitude modulate
5. A carrier wave of frequency 10 MHz and peak value of 10 V is amplitude modulated
by a 5 KHz sine wave of amplitude 6 V. Determine the modulation index and draw
the one sided spectrum of modulated wave.

6. Describe the time domain band-pass representation of SSB with necessary sketches.
7. Why VSB system is widely used for TV broadcasting - Explain?
8. Describe the single tone modulation of SSB. Assume both modulating and carrier
signals are sinusoids. Write SSB equation and plot all the waveforms and spectrums.
9. Explain the coherent detection of SSB signals.
10. Explain the envelope detection of VSB wave plus carrier.
11. Explain with block diagram, the phase discrimination method of generating SSB
modulated waves.

Unit-2
1. Describe generation of FM carrier by Transistor reactance modulator with necessary
diagrams.
2. Compare the phasor diagram of narrow band FM signal and AM signal and discuss
about the similarities and differences of the two signals
3. Compute the bandwidth requirement for the transmission of FM signal having a
frequency deviation 75 KHz and an audio bandwidth of 10KHz.
4. An FM radio link has a frequency deviation of 30 kHz. The modulating frequency is
3 kHz. Calculate the bandwidth needed for the link. What will be the bandwidth if
the deviation is reduced to 15 kHz?
5. Explain about FM generation using transistor reactance tube modulator.
6. Why are limiters and preemphasis filters used in FM radio.
7. Draw the black diagram of FM stereo broadcast transmitters and explain its
operation

Unit-3

1. Explain of the block diagram TRF receiver. Also explain the basic super
heterodyne principle.
2. Explain the operation of the double limiter and also AGC in addition to a limier.
3. Explain the purpose of pre emphasis and de emphasis circuits and the working of
these circuits.
4. Distinguish between simple AGC and delayed AGC.
a. Draw a block diagram of a super-heterodyne receiver and explain the
function of each stage.
b. What is meant by the term \tracking error"? Explain.

Unit-4

1. What is meant by Pulse Amplitude Modulation and explain any one-modulation


technique in detail.
2. What is meant by Pulse Width Modulation Explain the generation of Pulse width
modulation?
3. What is meant by Pulse Width Modulation Explain the demodulation of
Pulse width modulation?
4. What is meant by Pulse Position Modulation Explain the generation of
Pulse Position modulation?
5. What is meant by Pulse Position Modulation Explain the demodulation of
Pulse Position modulation?
6. Compare the performance of PAM, PWM, and PPM
7. What is Pulse modulation? Explain in brief various types of pulse modulation with
neat sketches
Elaborate how to avoid slope overload distortion in DM.
Illustrate the working of Adaptive DPCM with the help of diagram.
Illustrate the working of Adaptive DM with the help of diagram.
Explain the Companding in Adaptive DM
Explain
a)Channel Noise
b) Quantization noise in DM and derive expression for them?
Explain the need for non-uniform quantization in digital
communications.
Explain the Block diagram of DPCM system.
Discuss quantization error? How does it depend upon the step size?
Suggest some methods to overcome the difficulties encountered
depending on the modulating Amplitude swing?
Unit-5

Explain in detail about


i)FSK
ii)PSK with waveforms and equations
Determine probability of error for
a) ASK and
b) PSK systems.
a) Explain the demodulation of FSK using coherent detection.
b) Draw the block diagram of QPSK receiver.
Explain the generation of PSK signals.
Explain Differential phase shift keying modulation with neat block
diagram. Draw the wave forms

Explain the working of DPSK modulator and demodulator.

Explain a Baseband Signal Receiver.


Explain Optimum Receiver
With Neat diagram, explain Eye Diagrams
Explain Cross Talk which occurs in channel?
Why equalization is necessary in Baseband transmission? Give the block
diagram of adaptive filter and explain about each element.

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