Match List-X (Modulation/Reception Techniques) with List-Y (Disadvantages) and select the correct answer using the codes given be…

Question

Match List-X (Modulation/Reception Techniques) with List-Y (Disadvantages) and select the correct answer using the codes given below the lists:

List-X

i. Superheterodyne

ii. FM

iii. PCM

iv. Delta modulation

List-Y

1. Threshold effect

2. Granular noise

3. Image frequency interference

4. Quantization noise

1. A. i-1, ii-3, iii-4, iv-2
2. B. i-3, ii-1, iii-4, iv-2 (Correct answer)
3. C. i-1, ii-3, iii-2, iv-4
4. D. i-3, ii-1, iii-2, iv-4

Correct Answer

Option B — i-3, ii-1, iii-4, iv-2

Detailed Solution & Explanation

The correct answer is i-3, ii-1, iii-4, iv-2.

Key Points

• Superheterodyne — 3 (Image frequency interference): its characteristic weakness, since a signal 2 x IF away produces the same intermediate frequency as the wanted station.
• FM — 1 (Threshold effect): below a certain input carrier-to-noise ratio, FM performance collapses abruptly rather than degrading gracefully.
• PCM — 4 (Quantization noise): rounding each sample to the nearest discrete level introduces an irreducible error.
• Delta modulation — 2 (Granular noise): when the input changes slowly, the output hunts up and down about the true value.

Additional Information

• Delta modulation suffers a second characteristic defect, slope overload, when the input changes faster than the step size can follow — the mirror image of granular noise.
• Quantization noise power is Δ²/12, where Δ is the step size, so each extra bit of resolution improves the SNR by about 6 dB.