Accurate full spectrum test robust to simultaneous non-coherent sampling and amplitude clipping

For spectral testing of Built-in Self-Test Analog to Digital Converters, it is a very challenging task to precisely control the amplitude and frequency of input sinusoid signal. Amplitude over-range results in clipping ADC output and non-coherent sampling results in spectral leakage. In this paper, a new method is proposed that provides accurate spectral results even when the input to ADC is both over-ranged and non-coherently sampled. This relaxes the condition to have precise control over the input signal and thus decreases the cost. The method includes fundamental identification, removal and residue interpolation to obtain accurate spectral results. Simulations show the functionality and robustness of proposed method with both non-coherency and amplitude over-range. Measurement results of a commercially available 16-bit SAR ADC are used to verify the method for both functionality and robustness.