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Abstract

Methods and arrangements enable ADCs to be calibrated from reference signals with unknown parameters and/or with amplitudes that exceed the dynamic range of the ADCs. A given analog reference signal s(t) is supplied to an ADC. The output (x(k)) of the ADC is used by calibration logic to estimate at least one parameter of the reference signal. A FIR filter accepts as input the x(k) signals and outputs an estimate (s(k)) as the sampled instances of the s(t) signal. A reconstruction table is created that approximates the analog input signal in the digital domain using the knowledge of the analog input signal waveform type. The actual ADC outputs are compared to the values in the reconstruction table to produce a correction table for calibration. In an alternative embodiment, calibration logic interpolates the output (x(k)) of the ADC to reconstruct clipped portion(s) of the input analog reference signal s(t) when the amplitude of the input analog reference signal s(t) exceeds the full swing of the ADC. The FIR filter can thereafter use the reconstructed signal from the interpolation.

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