The GATE Grind

GATE 2024 EC – Question 46

Digital Circuits · Data Converters · 2 marks · Multiple choice

A full scale sinusoidal signal is applied to a 10-bit ADC. The fundamental signal component in the ADC output has a normalized power of 1 W, and the total noise and distortion normalized power is 10 μW. The effective number of bits (rounded off to the nearest integer) of the ADC is ______.

  1. 7
  2. 8
  3. 9
  4. 10

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Correct answer: (B) 8

Explanation

SINAD $=10\log_{10}\dfrac{1}{10\times10^{-6}}=50$ dB. ENOB $=\dfrac{\text{SINAD}-1.76}{6.02}=\dfrac{50-1.76}{6.02}=8.01\approx8$.