This is a design circuit for modulated current that is provided by the integrated rotational speed sensor KMI 15/x. This current signal must be converted to ground referenced voltage signal, matching the logic levels of the processing unit for digital signal processing. This signal conditioning can be done by using this circuit. This circuit is consists of protective elements to suppress line conducted interference and low pass filter in front of the comparator input. This is the figure of the circuit;
This circuit uses first-order RC low pass filter as signal filter. This circuit is made of C4 and R3 with cut off frequency of 10 kHz. This cut off frequency is used to achieve an optimum absorption of noise.
