Fetal Heart Rate Acquisition Signal Noise Filtering Circuit and Simulation
Fetal heart rate is noninvasively monitored by a silicon sensor during pregnancy.Fetal heart rate is a weak signal with low signal-to-noise ratio and strong maternal interference signal,which makes it very difficult to parse fetal heart signal.In this paper,a filter circuit of multistage MFB(Multiple Feedback circuit with infinite gain)based on single chip transceiver fetal heart rate me ter is proposed.This circuit amplifies and filters the weak fetal heart sound,and uses software simulation method to select the fi lter circuit parameters reasonably.The filtered and pre-processed heart rate signal is entered into the CPU for the autocorrelation algorithm to obtain the heart rate value.The final experimental results show that through this multistage MFB filter circuit,the signal to nois e ratio of fetal heart sound signal is high,and the high-frequency interference and most of the low-frequency signals are filtered out,while the fetal heart beat waveform is effectively preserved,so that the fetal heart rate can be accurately obtained by the fetal heart mete r probe within 30mm range,and the audio played by the loudspeaker with no noise.
NETL
NSTL
万方数据
维普
