This article presents a pulse-type ultrasonic Doppler fetal heart detection system. An ultrasonic probe based on pulse detection technology was designed, including a single piezoelectric ceramic chip transducer and an ultrasonic transmitting and receiving module. A pulse ultrasonic detection signal transformation model was constructed, and a fetal heart detection system was built, which was composed of a main control module, a timing control module, an ultrasonic transmitting module, an echo receiving module, a signal demodulation module, a signal conditioning module, a human-computer interaction module, a Bluetooth communication module, an output processing module, a power management module, and other key circuits such as four-level low-noise amplifier and filter were designed. The designed system was tested according to JJG 893-2007 Ultrasonic Source of Ultrasonic Doppler Foetal Meters, and its indication error and repeatability of fetal heart rate can meet the requirements of JJG 893-2007. Meanwhile the designed system can complete fetal heart detection efficiently and accurately.
This article presents a novel design of integrated human vital signs simulator, whose function includes the simulation of blood oxygen, blood pressure and ECG. According to the light transmission model basing on the optical properties of biological tissues, the pulse oximetry simulation module is designed, including its overall structure, a analog finger, a light source driving circuit, etc. The non-invasive blood pressure simulation module is designed basing on oscillographic method, and a piston rod type variable air chamber pulse waveform generation mechanism is included, using PWM constant current control and ultra small subdivision technology to control the linear motor to achieve stable and accurate displacement, and the pulse wave is simulated according to the blood pressure envelope. ECG verification waveform is generated by STM32F407 chip basing on ARM. The experimental verification results show that the designed simulator can meet the requirements of JJF 1470-2014 Calibration Specification for Multiparameter Physiological Simulators, and can complete the measurements efficiently and accurately.
Oxygen index measuring instrument is used to measure the minimum oxygen concentration required for sample combustion in a mixture of oxygen and nitrogen gas under specified test conditions. However, there is no national calibration specification for the instrument, the metrological traceability system for oxygen index measuring instrument has not been established in China currently, and there is no means to evaluate the metrological performance of the instrument. This article proposes an effective calibration method for oxygen index measuring instrument by determining and studying its key technical parameters, basing on the analysis of the structure and measurement principle of oxygen measuring instrument, and combining with the national standard GB/T 2406.1-2008 Plastics - Determination of burning behavior by oxygen index - Part 1: Guidance. The experimental results show that the proposed calibration method is scientific and feasible. Furthermore, the uncertainty of the calibration results is evaluated, which proves that the calibration method is scientific and practical and provides reliable technical support for the quality insurance of oxygen index measuring instrument.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.