It also gives a safety design problem analysis using an electret capacitor microphone to pick-up the heartsound signals.
该电路涉及到放大、滤波、电平抬升等电路，并给出了安全设计问题，利用驻极体电容传声器来拾取心音信号。
2
The clinical experiments have indicated that the first and second heartsound can be almost acquired by the microphone, but it is difficult for the third and fourth, w…