The Doppler fetal heart rate monitor is a handheld ultrasound transducer that uses the Doppler Effect to provide an audible simulation of the heart beat and displays the number of beats per minute.
To achieve this, acoustic waves are sent to the heart of a fetus inside the mother’s womb. Part of the energy bounces back; however, because the heart is beating, the bounced waves will be affected by the Doppler Effect, which changes their frequency.
An ultrasonic probe is a key component in the system. The probe contains an oscillator to generate ultrasound frequency followed by an amplifier to condition the sine wave in the order of volts.
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