ECG and noise from cables

ecg noise

Hi.

Recently I noticed that the type of cable have great significance to the 50 (60) Hz noise in my ECG amplifier. And by type I do not mean if it is screened, twisted and such things but the wire type. I fI use a soft silicone cable with large copper area and get much higher noise than if I use ordinary thin cable from a flat cable.

I have read about "low noise" cables and that may be something to use.

Anyone who knows more about this?

Regards,
Bengt

ecg with noise

50 or 60 Hz noise is becuz of power lines and u can use a simple filter (RC) to delete it!

ecg cables canada

That was fun. Do you know anything about measuring ECG? If you for example use an ordinary non-inverting OP-amp circuit and amplifies the ~500 times to get the ECG signal, you will have a 1000% saturated output because of that the power noise is so very much higher than your signal. You must use an instrumentation amp circuit with good CMRR. But still, you may have to much 59/60 Hz noise.

Got the picture?

I forgot to tell that much of your signal is in the same region as the noise so filtering is not an alternative in many cases.

reducing ecg noise

shoul use an very sharp notch filter in 50/60 hz

notch + 50 hz + op

Use coaxial cable and onnect the core to sensing electrode and the chees to ground to reduce the picked up noise.

But 50 Hz noise should be removed by 50 Hz notch filter

If you have a design for this filter send it please

ecg thin cable

Hej Bengt,

"Low noise" cable should make no difference in this case.

As a lab exercise at school we once built an ECG amplifier by stepwise
refinement of the circuitry until we got a pretty good result. I don't recall
what cable we used, but I don't think it was anything special.
I might be able to dig up my lab notes if needed.

Generally speaking, when twisting wires one should consider the thickness
of the insulation, which introduces a gap between the conductors. In this
sense I would guess that twisted wire-wrap wire would give a better result
than "fat" insulation types.

ecg 50 hz 60 noise circuit

can you show the ecg amplifier that you use at lab exercise at school?
tanx

50 hz notch filter rc

the options is always there at both end..

u can use twin t notch filter at the designed board without anymore gain..
i,e surpress noise...

or software end you can go for LPF design to reduce these noise...

happy

ecg 60 hz noise

If you notch out 50Hz then you still have all its harmonics at 100Hz, 150Hz, 200Hz etc.

If the circuit has good common-mode rejection then a notch filter is not needed.

Finally I answer my own question. Copper cables do generate noise. The wires will induce an inductive current just because of the movement though the earth magnetic field and this small current can be a problem for very high sensitive sensors. Therefore there are non magnetic cables that is used to for example ECG.
Probable this cables will also take up less 50/60 Hz noise as well depending if it is inductive or capacitive noise.
So that was it.

For simple school lab tests with much less requirements you can of course get a reasonable good signal with normal cables, it is easy. But could you stop giving these suggestions about notch filter? As I said, 50-60 Hz is right in the middle of the signal frequency range and you can of course not filter away the signal you are interested in. I maybe should have mentioned it bit I am not a newbie in designing ECG amplifiers.