why is the frequency of an ECG signal so different from the frequency of a humanbody’s ECG ?


I’m a medical student doing an experiment about EKG. when I measured the frequency of the signal I got 1250 Hz which is so huge compared to the typical heart beat frequency of a person usually around 60 bpm or 1.067 s^(-1)

In: Physics

I guess you mean the sampling frequency.

Assuming that. The more samples you have the better you can reconstruct the sampled signal.

If you only need to count heartbeats, you could use the max supported heartbeat times 2 (see Nyquist theorem). That will give you at least the count of heartbeats.

If you want to see details on the signal, you need to sample at least twice the speed of the smallest detail you want to see.

When looking for a patient’s ECG I’m pretty sure you are interested on the max amount of details you can see. Otherwise you will miss a heart attack

it’s called super sampling. the more times you sample the more sensitive you are to changes. if you look at a EKG, you see it has several phases for a heart beat. not just a 0 for when it’s not beating and a 1 for when it’s beating. you have the whole PQRST phases and the associated curves and segment/intervals with those phases. so you need to detect all of that, for one heart beat. so if you beat 60 times a minute, you’ll miss all that info if you sample at 60hz. and heart bpm’s can easily go up to 200-220bpm so that’s why your sampling interval is so high.