JAJSLQ5C April 2021 – September 2022 ADS127L11
PRODUCTION DATA
Signal-to-noise ratio (SNR) is a measure of noise performance with a full-scale ac input signal. For the SNR measurement, a –0.2-dBFS, 1-kHz test signal is used with VCM equal to the mid-supply voltage. As shown in Equation 11, SNR is the ratio of the rms value of the input signal to the root-sum-square of all other frequency components derived from the FFT result of the ADC output samples. DC and harmonics of the original signal are excluded from the SNR calculation. In a test case where an FFT window function is used because of non-coherent sampling, the spectral leakage of adjacent frequency bins surrounding dc, the original signal and signal harmonics are removed to calculate SNR.
where: