Ferrer Arnau, Luis Jorge

Parisi Baradad, Vicenç

Roset Juan, Francesc Xavier

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17th TC-4 Workshop IWADC on ADC and DAC Modeling and TestingJuly 18th and 19th 2013   Barcelona 69   Defining frequency domain performance of Analog-to-Information Converters  Decimator filter based on B-splinesDoris Bao163, Pasquale Daponte163, Luca De Vito163, Sergio Rapuano163Lluís Ferrer-Arnau164, Xavier Roset165, Vicenç Parisi-Baradad165The paper deals with the definition of dynamic performance of Analog-to-Information Converters (AICs). These compo-nents allow to overcome the sampling frequency limits of the Shannon theorem, by assuming that the observed signal has a sparse representation in a given domain. The paper aims to verify the behaviour of standard parameters currently defined for Analog-to-Digital Converters when applied to these new devices. To this aim, several simulations and experimental tests have been carried out to study the influence, in the fre-quency domain, of quantization noise and nonlinearity on the AIC dynamic parameters.There are many applications that require high resolution AD conversion, mainly based on sigma delta converters. An im-portant component of these converters is the digital filter is applied before decimating the oversampled signal. The main characteristics of a decimation filter are its discrimination abil-ity, close  to a rectangular frequency response which is equiv-alent to an ideal sinc filter. We know that this ideal filter has infinite impulse response, thus it’s  implementation with a FIR filter always supposes the  truncation at some point. This pa-per proposes a filter based on B-splines, called least squares filter, which has already been proposed for digital image in-terpolation. The innovation proposed here is a version of this FIR filter, which is much easier to implement than the original. The advantage is that this filter combined with an interpolator filter also based on B-splines achieves a very good frequency response that approximates the ideal band limiting filter. Ad-ditionally we compare it with a commonly available decima-tion FIR filters encountered in commercial integrated AD con-verters.PSDs of the AIC output signal for values of ε equal to 0.8 and 0.05, respectively.FIR approximation of the least squares filter FIR, using 20 coefficients.21AD17022BP103

Decimator filter based on B-splines

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