Characterization of high resolution DAC by DFT and sine fitting

The research concerns with the evaluation of the dynamic performances of the DAC by analysing, in the frequency domain, the estimated output signal characterised by non uniform sampling. The non uniform sampling is caused by the method used to acquire the signal with both high resolution and linearity. On the basis of this characteristic, the signal processing in the frequency domain by tradition procedures brings non correct information. In order to overcome this problem two different analysis procedures are taken into account able to correctly process the non uniformly sampled signal. One is based on the discrete Fourier transform modified to be used in the case of non uniformly sampled signal. Another one is based on the multi-sine fitting algorithm modified according to the procedure presented in the paper. The performances of both the two analysis procedures are evaluated and highlighted. In particular, the accuracy of two analysis procedures is compared to evaluate the total harmonic distortion and the spurious free dynamic range in various experimental conditions.