A fetal doppler is an electronic instrument used for fetal heart monitoring, primarily to calculate fetal heart rate. The most widely used type on the market is the doppler fetal monitor, which is generally based on ultrasound doppler technology and requires only a low ultrasound dose. A healthy fetal heart rate varies constantly with conditions inside the uterus; this variability reflects the normal regulatory function of the central nervous system and indicates that the baby is in good condition in the womb. The purpose of fetal heart monitoring is to detect fetal abnormalities as early as possible so that effective emergency measures can be taken and the newborn delivered in time, before the fetus suffers irreversible damage that could affect it for life.
Solution Overview
Our solution uses an HDSC HC32L series chip as the main controller, supports a low-cost LCD display, and pairs a cable-type ultrasound probe built around a high-sensitivity precision crystal with a fast detection algorithm, so an accurate fetal heart rate reading is obtained quickly and the fetal heartbeat is easier to hear. The ultrasound probe also supports noise reduction, filtering out weak background sounds from inside the uterus and greatly reducing static noise for a clearer fetal heart signal. After noise reduction, the fetal heart sound is amplified by an op amp and fed directly to the 12-bit ADC inside the MCU for sampling and processing. The home fetal doppler solution supports listening to the fetal heartbeat through headphones or through a loudspeaker for higher sound intensity, allowing the fetal heart rate signal to be obtained quickly and accurately at home.
Recommended MCU
- HC32L series: HC32L136 — high detection accuracy and high reliability based on a large, high-sensitivity ultrasound probe; intelligent noise reduction with strong interference immunity; upgraded audio output supporting headphone and speaker playback; cable-type probe with low-cost LCD display; power on/off switch and automatic shutdown on timeout; handheld design that is compact, simple to operate and easy to use
Core Components
- MCU: HC32L136 (HDSC)
- LDO: ZL6205 (ZLG Microelectronics)
- DC-DC: MPS, full part number available on request
- Op amp: 3PEAK, full part number available on request
- Audio power amplifier: ISSI, full part number available on request
Functional Block Diagram
