With low pass filter use Bessel for least amount of overshoot in the time domain, and Cauer (or elliptic) for fastest rolloff in the freq domain.

• （设计低通滤波器时选用贝塞尔型可以使时域较平坦，没有太多过冲，选用切比雪夫可以提高截止频率的陡峭性。）