Low pass filter for ECG signals design notes

On second thought, if the ECG signal frequency is only 10Hz, which is much lower than the line frequency of 50Hz, then actually I am having luck, because I can use a low pass filter of say 10Hz or 20Hz, to filter all high frequency noises including 50Hz line noise.

So I used the muzique calculator again, and got the RC pair of 2.2uF and 7K to start my low pass filter trials and errors design.

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Simple R-C Filter Cutoff Calculator - Muzique.com Lab Notebook

http://www.muzique.com/schem/filter.htm

The simple R-C filter rolls off the frequency response at 6 dB per octave above the cutoff frequency. The position of the resistor and capacitor are switched to change from low pass to high pass but the same calculation applies to both filters. This calculator assumes a low source impedance, which usually is small enough that it does not change the corner frequency.
Input any two values in the form boxes and hit the Calculate button to find the remaining value.

Capacitor (uF) = 2.2 uF, Corner Frequency (Hz) = 10 => Resistor (ohms) - 7.238K

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