New Estimators and Guidelines for Better Use of Fetal Heart Rate Estimators with Doppler Ultrasound Devices

Figure 3

General diagram of the Doppler data processing acquired using one transducer and one channel. 𝑥_𝐹 and 𝑥_𝐵 represent the envelopes of the directional signals, and 𝑥_𝑒 represents the envelope of the nondirectional signal. 𝐼₁, 𝐼₂ are the two autocorrelation estimators.