Processing of bidirectional exponential stimulus in ADC testing

ADC histogram test methods with exponential stimulus are ADC test methods alternative to sine wave testing. Exponential stimulus test methods published until now were based on simple, single-component exponential pulses. This can sometimes partially mask nonlinearity of ADC transfer characteristics. Moreover, estimation of pulse parameters in time domain requires memorizing and processing long records. The new approach is based on the exponential ADC stimulus with two or more different exponential components, e.g., rising and falling slopes of exponential pulses that can be generated very simply and with low costs. Moreover, the different way of signal processing using histograms instead of time record is introduced. Unknown parameters needed for estimation of INL and DNL are calculated by LS fitting using simplified Newton method. The new test method was verified by simulations and experiment.