ECG application

[chenjk09]

Hi,

Can anyone explian to me how the ECG Front End Work?

I understand that
-INA326 supply the gain of 5.
-ADS8321 is an ADC.
-A1 and A2 is reject 50/60-Hz noise.
-those capacitor parallel to resistor is cancels resistor noise.

I would like to understand the circurt
Please help me
Thanks

 

[audioguru]

A1 and A2 are DC-coupled so they cancel DC and all low frequencies which are called common-mode (the same interfering signals on both inputs).
The instrumentation amplifier has common-mode rejection much better than you can make with your own opamps and resistors.

Most of the capacitors create negative feedback in an opamp which makes a lowpass filter.

 

[chenjk09]

Hi
Thanks for the reply

Is there and band pass filter in the circurt?

 

[audioguru]

Is there and band pass filter in the circuit?

A bandpass filter is a lowpass filter that cuts off high frequencies and a highpass filter that cuts off DC and very low frequencies.
There are a few lowpass filters but since there are no coupling capacitors (the circuit is completely DC-coupled) then it has no highpass filters.
Maybe the A to D converter is programmed to be a highpass filter.