Calculating Signal-to-Noise-and-Distortion Ratio (SNDR) and Spurious-Free Dynamic Range (SFDR) for Analog-to-Digital Converters (ADC)

This text provides an in-depth discussion of computational functions for Signal-to-Noise-and-Distortion Ratio (SNDR) and Spurious-Free Dynamic Range (SFDR) in Analog-to-Digital Converters (ADCs). ADCs are circuits widely used in signal acquisition and processing systems. Unlike traditional analog circuits, ADCs convert input signals into digital format for subsequent processing in the digital domain. SNDR serves as a critical performance metric for ADCs, representing the ratio between the signal power and the combined power of noise and distortion components. SFDR measures the ratio between the fundamental signal and the largest spurious component in the ADC output spectrum. Understanding how to calculate SNDR and SFDR is therefore essential for evaluating ADC performance. Code implementations typically involve Fast Fourier Transform (FFT) analysis of ADC output data, where the fundamental tone magnitude is compared against noise floors and harmonic distortions across specified frequency bins. Key algorithmic steps include windowing the time-domain data to minimize spectral leakage, identifying harmonic locations based on the input frequency, and integrating noise power while excluding distortion components from the calculation.