The blood flow frequency imaging of peritrophoblastic artery flowing was searching by pulse Doppler, it was high extending flow and low resistance.
用彩色能量图显示低速血流，用脉冲多普勒寻找高舒张期低阻力滋养动脉血流频谱。
2
Introduction was made to the method of sine pulse width modulation (SPWM) wave generated by table searching, which is based on area equivalence principle.