GATE 2021 BM – Question 17
The input Vᵢₙ=sin(2π×10⁶t) is quantized by a 10-bit Nyquist ADC. Four least significant bits are discarded, and the remaining six most significant bits drive a 6-bit DAC. Assuming uniformly distributed quantization noise, find peak SQNR at the DAC output in dB.
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: (D) 37.88
Explanation
After discarding four bits, effective output resolution is six bits. For a full-scale sinusoid and uniformly distributed quantization error, SQNR≈6.02N+1.76 dB. Substituting N=6 gives 36.12+1.76=37.88 dB, D. Keeping the original ten-bit SQNR would ignore the information discarded before the DAC.