Abstract
Phonocardiograph has made great progress in regard to the graphic registration for the auscultatory phenomena as percieved by the human ear. However, some problems that are essential to phonocardiography especially its standardization have remained unsolved.
The problems are :
First, to calibrate a microphone accurately under the similar conditions to actual use; Second, to analyze the frequency-intensity characteristics of heart sounds and murmurs by using the calibrated microphone;
Third, to design the filter system based upon the results obtained by the above method.
Current situation of above problems and of others in phonocardiograph is reviewed.
