Signal processing methodologies for an acoustic fetal heart rate monitor

Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use

The Generalised Instrument

Thesis (M.E.Sc.) -- University of Adelaide, 199

A full field, 3-D velocimeter for microgravity crystallization experiments

The programming and algorithms needed for implementing a full-field, 3-D velocimeter for laminar flow systems and the appropriate hardware to fully implement this ultimate system are discussed. It appears that imaging using a synched pair of video cameras and digitizer boards with synched rails for camera motion will provide a viable solution to the laminar tracking problem. The algorithms given here are simple, which should speed processing. On a heavily loaded VAXstation 3100 the particle identification can take 15 to 30 seconds, with the tracking taking less than one second. It seeems reasonable to assume that four image pairs can thus be acquired and analyzed in under one minute

A digital signal processor based optical position sensor and its application to flexible beam control

A Digital Signal Processor (DSP) based optical position sensor was developed. The sensor system consists of the following components: 1) analog electronics, 2) the DSP based synchronous demodulation software, 3) PC based interface software which samples and saves the data, and 4) PC based control codes for a flexible beam. experiment. The ability of the system to determine the distance from the optical sensor to the power modulated light source was assessed by the following tests: 1) a stationary drift test to evaluate the system\u27s noise, 2) a short-range test to determine the resolution of the optical sensor over a 25mm range and, 3) a long-range test to evaluate the ability of the system to predict the location of the optical sensor over a 600mm range. It was found that the resolution of the system is approximately 0.5mm for the short range test and 5mm for the long range test. Finally, the sensor was deployed for the position feedback of a flexible beam experiment. Performance indices used to evaluate the response of the system were: 1) the sum of the squared position error, 2) the final steady state position error of the end of the flexible beam, and 3) the 5% settling time of the flexible beam. A number of control laws were evaluated and it was determined that a variable PID controller produced the best overall performance. The system can consistently position the end of the flexible beam from a +1-20cm to within 5mm of the command position in approximately 8 seconds with a properly tuned controller

RAPID CLOCK RECOVERY ALGORITHMS FOR DIGITAL MAGNETIC RECORDING AND DATA COMMUNICATIONS

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