There are signals like below picture inputted to MCU STM32f103: (Offset DC about 800mV, Vmax = 2.4V, f = 66 Hz)
I want to change it to a squar wave from 0V to 3.3V being accepted voltage range for my MCU. How I can implement it? Using a schmitt trigger implemented by an op amp? Can you please provide me a schematic?
Based on ChrisStratton`s comment: Cost and power do not matter. I am going to obtain frequency of signal by MCU Timer/Counter. In fact my ultimate goal is to have the frequency to calculate speed. One hertz could be an accepted precision and the frequency is less than 1 KHz. Actually the first thing I tried was AC coupling being able to remove DC offset. However, the amplitude was not what I want. To sum up, I need to have a square wave with the same frequency and 0 V to 3.3 V amplitude.