Quantization error relation to ADC resolution?

• A. Higher ADC resolution increases quantization error.
• B. Quantization error is independent of ADC resolution.
• C. Quantization error only depends on sampling rate.
• D. Higher ADC resolution reduces the step size and quantization error.

Answer: (D)

Quantization error is tied to how finely the analog signal is sliced into discrete levels. The step size between adjacent levels, Δ, determines how far the true analog value can lie from the quantized value. For an ADC with full-scale range VFS and N bits, Δ = VFS / 2^N. The error for any sample is bounded by ±Δ/2 because the true value falls somewhere within half a step of the chosen level. So, when you increase resolution (more bits), you create more levels, Δ gets smaller, and the quantization error shrinks correspondingly. The sampling rate affects how often you sample but not the amplitude of the quantization error. That’s why higher resolution reduces the step size and the quantization error.