Abstract
In this study, we focused on the study of recording method which is hardly influenced by ambient noise.
We carried out the noise tolerance experiment which evaluates the influence on quality of recording by
ambient noise environment in 4 kinds of recording methods, then compared and evaluation its.
In the result, recording methods by piezoelectric transducer were hard to be influenced by ambient noise.
And we clarified that if the noise doesn't be mixed in frequency band of heart sound, influence of noise
could be controlled without the decay of quality of recorded heart sound by using low-pass filter which can
cut frequency band higher than heart sound.
