UNIT-III
1. Explain the working of a balanced slope detector with a neat circuit
diagram and waveform sketches. Also, analyze how it overcomes
the limitations of a simple slope detector.
2. Compare the Amplitude Modulation (AM) and Frequency Modulation
(FM) techniques
3. Derive the expression for the output of a Phase Locked Loop (PLL)
used for FM detection. Illustrate its working principle with the help of
a block diagram
4. A 93.2 MHz carrier is frequency modulated by a 5 kHz sine wave.
The resultant FM signal has a frequency deviation of 40 kHz.
i. Find the carrier swing of the FM signal.
ii. Determine the highest and lowest frequencies occupied by the
frequency-modulated signal.
iii. Calculate the modulation index for the wave.
5. Explain the Armstrong method of generating FM signals with neat
block diagram.
6. What is the difference between direct and indirect methods of FM
generation? Explain the working of a balanced frequency
discriminator with the help of circuit diagram
UNIT-IV
1. Compare low-level and high-level AM transmitters in terms of
modulation stage, power handling, efficiency, and application.
Support your answer with a block diagram for each.
2. List and explain the key characteristics of a Superheterodyne
Receiver.
3. Explain the working principle of a Variable Reactance Type FM
Transmitter and draw its block diagram
4. Describe the working of a Tuned Radio Frequency (TRF) receiver and
discuss its advantages and disadvantages.
5. Classify radio transmitters based on the modulation technique and
frequency range. Explain the characteristics and applications of
each type with suitable examples.
6. Explain the principle of a Superheterodyne Receiver with a neat
block diagram and discuss its significance in communication
systems.
7. Describe the concept of Automatic Frequency Control (AFC) and
explain how it contributes to frequency stability in FM transmitters.
8. Explain the principle of a Superheterodyne Receiver with a neat
block diagram and discuss its significance in communication
systems.
9. Define and explain the concept of "tracking" in superheterodyne
receivers.
10. Define frequency stability and its importance in FM transmission.
11. Draw and explain block diagram of double conversion FM
receiver.
12. What is the significance of AGC circuit? Differentiate between
simple, delayed and amplify AGC and explain the function with the
help of neat diagram
13. Draw the block Schematic for FM broadcast receiver and
explain the function of each unit.
14. Draw the block diagram of FM Transmitter and explain the
function of each block in detail.
15. Explain the following terms in detail
(i) Amplitude limiting (ii) Frequency changing and tracking
16. In a broadcast Super Heterodyne Receiver having no RF
amplifier is tuned to 555kHz. The local oscillator frequency is
adjusted to 1010kHz and the quality factor is 100. Calculate the
intermediate frequency, image frequency and image rejection ratio.
17. Compare AM and FM receivers.
UNIT-V
1. Derive the expression for the Figure of Merit (FOM) of a Double
Sideband Suppressed Carrier (DSBSC) system.
2. Explain the detection process of Pulse Width Modulation (PWM) with
the help of a block diagram and neat waveforms.
3. Derive the expression for the Figure of Merit (FOM) of an Amplitude
Modulation (AM) system considering noise effects.
4. Compare Time Division Multiplexing (TDM) and Frequency Division
Multiplexing (FDM) in terms of principle, operation, advantages, and
limitations.
5. Explain the concepts of Pre-emphasis and De-emphasis in
communication systems. Why are they used, and how do they
improve the signal quality?
6. Explain the generation and detection process of Pulse Amplitude
Modulation (PAM) with the help of block diagrams.
7. Derive the expression for the Figure of Merit (FOM) of a Single
Sideband (SSB) system.
8. Describe the generation and detection of Pulse Position Modulation
(PPM) with neat block diagrams.
9. Draw and explain the generation of Pulse Width Modulation (PWM)
with waveforms.
10. With a neat sketch explain the generation of PPM from PWM.
11. What is FM threshold effect? How threshold reduction is
achieved in FM receiver in detail.
12. What is noise? Explain the difference between thermal noise
and shot noise in detail.
13. Explain the threshold noise effects in angle modulation system
with suitable diagrams?
14. Draw the block diagram of Time Division Multiplexing and
explain the function of each block in detail.
15. Compare PAM, PWM and PPM systems.
