A Research Of Heart Sound Generator And Multiple Process Instrument Based On LabVIEW

Virtual instrument is a new kind of instrument coming out with the development ofmicrocomputer and software. All hardware and software in one platform can be shared freelyamong modules. So it's very quick and convenient to construct auto-test systems using virtualinstrument technology. It points out the direction of modern instrument. At the same time, theacquisitionandanalysisofheartsoundpossessagreatvalueinclinicaldiagnosis,scientificresearchand teaching. The time domain analysis and frequency domain analysis can help doctors andresearchers to deal their work more effectively. And they can have not to collect sorts of cardiacsounds using a heart sound generator. More over, the heart sound generator can help students tolearn the character of kinds of cardiac sound more quickly. So it's meaningful to develop a kind ofvirtualinstrumentaboutheartsoundanalysisandsignalgenerator.A heart sound generator & multiple process virtual instrument is demonstrated in this thesis.Therearefivesubsystemsinthisinstrument:HeartSoundAcquisitionsubsystem,WaveletDe-noisesubsystem, Time Domain Analysis subsystem, Frequency Domain Analysis subsystem and HeartSoundGenerationsubsystem.The Time Domain Analysis subsystem (TDAS) and Heart Sound Generation subsystem(HSGS) are creative in this virtual instrument. The TDAS proposes a new method -- NormalizedEnvelopesegmentation&averagealgorithm--tocomputetheheart beat frequencyandheartsoundintervalwithgoodnoiseresistanceandhighaccuracy.Theapproachis:extracttheenvelopeofheartsound and normalize it first, then cut it into pieces to calculate the average cycle. While the HSGSfirstletusergetheartsoundsignalaswhattheywantonvirtualinstrumentdevelopedbyLabVIEW.The parameters setting are also discussed to find out the best for the each subsystem. All theparameterscanbesetbyuserandthebestonesaredefaultvaluessothattheinstrumentcanfitotherenvironment.The running test of this instrument proves it can collect vivid heart sound signal, reduce noiseeffectively,computerthecharacteristicvaluesquicklyandaccurately, generateandplayheartsoundprecisely.Itcanbeusedasanassistancetoshow,play,andanalyzeheartsound.