COMMUNICATION THEORY

S K C T

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

QUESTION BANK

SUB.NAME

: COMMUNICATION THEORY

YEAR /SEM : II / IV
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UNIT I
AMPLITUDE MODULATION SYSTEMS
PART-A (2 Marks)
1. Define Amplitude Modulation.
2. What is AM wave envelope?
3. Define modulation index for an AM wave.
4. List out the advantages of AM.
5. Define the transmission efficiency of AM signal
6. As related to AM, what is over modulation, under modulation and 100% modulation?
7. Define FDM .
8. Define SSB.
9. Mention the applications of SSB.
10. Mention the advantages of VSB.
PART-B (16 Marks)
1. (a).Explain the generation of AM signals using square law modulator.

(8)

(b).Explain the detection of AM signals using envelope detector.

(8)

2. Explain Balanced modulator to generate DSB-SC signal.

(16)

3. Explain coherent detector to detect SSB-SC signal.

(16)

4. Explain the generation of SSB using balanced modulator.

(16)

5. Draw the circuit diagram of Ring modulator and explain with its operation.

(16)

6. Discuss the coherent detection of DSB-SC modulated wave with a block diagram of detector and Explain.

(16)

7. Draw the block diagram for the generation and demodulation of a VSB signal and explain the principle of operation.

(16)

8. Write short notes on frequency translation and FDM.

(16)

UNIT II
ANGLE MODULATION SYSTEMS
PART-A (2 Marks)

1. Define PM.
2. Define FM.
3. Define Frequency deviation(∆f)
4. Define Carson’s rule.
5. Write the applications of FM
6. What do you mean by narrowband and wideband FM?
7. What is modulation index of PM?
8. Define Direct method and Indirect method FM.
9. Mention the advantages of FM.
10. What is the modulation index of FM?

PART-B (16 Marks)
1. Explain the indirect method of generation of FM wave and any one method of demodulating an FM wave.

(16)

2. Derive the