Comparising of antialiasing filters in A / D converters

Antialiasing filter belongs to professional converters of analog signals to digital signals. This filter is either built in the circuit of sigma-delta converters or a separate part of the circuit of the successive approximation convertors. The paper will deal with a simple measurement of RMS at the output of A/D conversion while at the input of the converters is a harmonic signal with frequency which belongs to the transition band of the antialiasing filter or is greater than the Nyquist frequency. Antialiasing filtration is important for digitalization of the random signals and the signals which are corrupted by a background noise.