Purpose -The purpose of this paper is to design a tool for IIR digital filters obtained from analog prototypes, which preserves simultaneously the amplitude and the group delay response. Design/methodology/approach -A new s-to-z transform is developed based on a second order formula used for numerical integration of differential equations. Stability of the newly obtained transfer functions in the z-domain is proved to be preserved. Distortions introduced by the new transform into the original amplitude and group delay responses are studied. Findings -The new formula, when implemented to all-pole prototypes, exhibits lower selectivity than the original while reducing the pass-band group delay distortions. In the same time its structure is importantly simpler than the functions obtained by the well-known bilinear transform. When implemented to a prototype having "all kinds" of transmission zeros the resulting filter has almost ideally the same characteristic as the prototype.Research limitations/implications -The new transform may be used exclusively to synthesize even order filters. The new function is twice the order of the analog prototype. This kind of transformations are used to design IIR digital filters only. Low-pass transfer functions were studied being prototypes for all other cases. Originality/value -This is a new result never mentioned in the literature. Its effectiveness is confined to a niche problem when simultaneous sharp selectivity and low group delay distortions are sought.

Artificial neural networks are applied for modeling the input and output circuits of the digital part of the digital–analog and analog–digital interface, respectively, in CMOS mixed-mode circuits. The generalization property of the neural networks is exploited to apply the models in a set of previously unknown situations, the most important being loading the model generated from the unloaded circuit. The models developed are applicable in mixed-signal behavioral simulations.

The paper suggests a new and efficient method for location of nonlinear loads on a grid. It is based on measuring of distortion power. The paper reviews different definitions of distortion power and proves that the method is feasible independently on particular definition. The obtained results of simulation and measurement confirm the effectiveness and applicability of the method. The proposed solution is suitable for software update of existing electronic power-meters or can be implement as hardware upgrade.

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