Recently have been reported methods to deliver a digital filter from an analog active filter, described only by its circuits diagram. The proposed approaches have been implemented in MATLAB and Python, and they were based on state-space conversion from analog to digital domain. Based on the Python approach, we show in this paper how to compute the transfer function of a large order analog active filter. The analog filter is described only by its circuits diagram. Finally, the analog filter is converted to the corresponding digital filter, having similar frequency gain and phase characteristics.
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