ECG signal amplication

RE: ECG signal amplication

Former Member — Tue, 30 Dec 2014 06:31:37 GMT

Design and development of medical devices should be according to the guidance of FDA. It will ensure you about good quality of medical device which will never fail during real use. There are frameworks given for manufacturers to develop and implement design controls. However, most important concern to look out is the medical device security from cyber attack.

RE: ECG signal amplication

Former Member — Tue, 23 Dec 2014 10:44:11 GMT

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RE: ECG signal amplication

dougw — Sun, 11 May 2014 19:03:27 GMT

Here is a typical first amplifier stage (from the internet) showing the driven shield and leg reference:

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RE: ECG signal amplication

sunnyiut — Sun, 11 May 2014 18:04:40 GMT

Hello,

between 1 and 5mV !!! or 0 and 3.3V? I think the GPIO has input voltage 0v and 3.3v

however, diagnostic systems use 12 LEAD ECG, but for monitoring purpose u just need 3 LEADs [limb leads]. Frequencies between 0.05Hz to 150Hz would be good enough. For just monitoring a single Lead the following block diagram can meet the purpose. While you may need to vary the 2nd stage gain [Gain-25] according to your voltage range. A level shifter will be necessary if you use dual power supply.

Say for LEAD1 you need to connect the LA at the non-inverting input of INA [instrumentation amplifier] and the RA at the inverting input. You will need another electrode which will be connected at the RL as reference [GND]. You can go for RLD [right leg drive] to reduce the line power noise. where the signal is inverted and driven back into the patient through the right leg by an amplifier. you can get the signals without RLD, but it will be a little bit noisy. as you are using Pi, you can implement a 50/60Hz notch filter in your firmware which will improve the signal a lot.