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ADC Quantization Noise Calculator

Calculate ADC quantization noise, theoretical SQNR, ENOB, dynamic range, and noise spectral density for analog-to-digital converter design.

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Formula

SQNR=6.02N+1.76 dB,LSB=Vref2NSQNR = 6.02N + 1.76 \text{ dB}, \quad LSB = \frac{V_{ref}}{2^N}
NADC resolution (bits)
SQNRSignal-to-quantization-noise ratio (dB)
LSBLeast significant bit voltage (V)
V_refADC reference voltage (V)

How It Works

Quantization noise is an inherent limitation in analog-to-digital conversion where continuous analog signals are transformed into discrete digital representations. When sampling a signal, an analog-to-digital converter (ADC) approximates the continuous signal's amplitude using a finite number of discrete levels, introducing quantization error. The quantization noise is a form of signal distortion that depends on the number of bits used in the analog-to-digital conversion process.

Worked Example

Problem: Calculate the Signal-to-Quantization Noise Ratio (SQNR) for an 8-bit ADC and determine the least significant bit (LSB) voltage if the reference voltage is 5V Solution: 1. SQNR Calculation: SQNR = 6.02 * 8 + 1.76 = 50.32 dB 2. LSB Calculation: LSB = 5V / (2^8) = 5V / 256 = 0.01953V 3. This means each quantization level represents approximately 19.53 mV

Practical Tips

  • Use oversampling techniques to improve signal-to-noise ratio
  • Select ADC with appropriate bit resolution for your signal requirements
  • Consider dithering techniques to reduce quantization noise

Common Mistakes

  • Assuming higher sampling rate always improves quantization noise
  • Not accounting for reference voltage when calculating LSB
  • Neglecting the impact of bit resolution on signal-to-noise ratio

Frequently Asked Questions

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