Hi all,
Since noise in one form or another seems to be a popular topic here at present, I have a question relating to it. This heart monitor I've been playing with lately is astonishingly good for the price; I really can't significantly fault it. But you can't expect perfection for five quid. I've noticed there is a small amount of noise riding on the output signal, depending on one's body posture for some reason. The noise closely resembles a triangle wave and its frequency is 200Hz. What's the best solution filter-wise for removing it? I obviously wish to avoid any attenuation of the positive peak of the QRS complex; the only sharp transient present on a normal ECG trace. Here's a diagram showing once whole cycle of a regular trace:
So... Best flavour of filter for this particular application, please?