这是双频测心率法的原理文档，做该项目时很有帮助-This is the dual principle of measuring heart rate law documents, the project is helpful to do

An ECG is used to measure the heart’s electrical conduction system.[4] It picks up electrical impulses generated by the polarization and depolarization of cardiac tissue and translates into a waveform. The waveform is then used to measure the rate an