Modified Low-Frequency Filter for Signal Spectrum Limitation at Analog-Digital Converter’s Input with Differential Input

Abstract

We have considered a modified architecture of the third order low-frequency filter (LFF), intended to be applied as an anti-alias filter on inputs of analog-digital converters (ADC’s) with differential input. We have obtained conditions for low-frequency filter’s circuit parametrical synthesis. We have shown results of suggested LFF simulation and compared its amplitude-frequency characteristics (AFC’s) at different frequencies of applied operational amplifiers’ (OP-AMP’s) unity gain (AD8132, THS4131).