The Design Of The Blood-pressure Meter With The Wave-display

The blood pressure is one of the most important human physiologicalexponents, the appropriate blood pressure can keep metabolismnormal.The same time,the blood pressure can also reflect the function ofthe heart and the blood vessel.The measure of the blood pressure has beenused to the prophylactic.On the other hand ,it's required to do the continuousblood pressure measure for the dangerous patients,it can not only prevent thedanger,but also help the doctors.In resent years, hypertension continuallyhappens to the agedness people,so we need the small usefulelectro-sphygmomanometer.The blood pressure comes from the bloodcirculation. The chamber on the left side of the heart that receives arterialblood from the left atrium and contracts to force it into the aorta. Thechamber on the right side of the heart that receives venous blood from theright atrium and forces it into the pulmonary artery.And then the bloodmoves in circles.The highest pressure is called shrinkage pressure when theheart shrinks,which puts the blood into the aorta and keeps the bloodcircle.The lowest pressure is called deploying pressure when the heartdeployed,which forces the blood back to the chamber on right.The bloodpressure reflects the heart ability of pumping blood,boold capacity of thebody,the physical state of the blood,etc.So the blood pressure is veryimportant.Firstly,we introduce the characteristics of the bio-electricity signal and theblood-pressure signal,which are the base of the design. The characteristic ofthe biology system is complex structure.Strickly,the biomedicine signals arestochastic.So it's hard to deal the signal.The blood-pressure signal isperiodic ,which can move with the body's change.Since 1628 people try tofind a advantageous method to measure the blood pressure.We try tomeasure the blood pressure with the method of wave-display. The principleof the wave-display is that the blood-pressure wave is tested after the arteryblood is interdicted.It's small wave when the whisht wave is bigger than theshrinkage pressure;the wave will increase when the whisht pressure issmaller than the shrinkage pressure;the wave will be the biggest when thewhisht pressure equals to the average pressure;then the wave will be smallerand smaller when the whisht pressure is smaller than the deployingpressure;the wave will keep small when the whisht pressure is smaller thendeploying pressure.In this disquisition,we stress the choice of the pressure sensor and the signalof the blood pressure.The human blood pressure is usually between 0 to20kPa,which is more smaller than the pressure signal in the engineeringproblem.On the other side,the blood pressure must be caculated.So thepressure sensor must have the perfect matching.MPX2100 is satisfactory.Thehuman sphygmus is matches the heart-throb,and the sphygmus is influencedby the age and sex.It's 90-100 in babyhood and 70-80 in manhood.Thesports and felling can influence the blood pressure too.From that,we can seethat the wave of the blood pressure is a low-frequency signal,which used be1-2Hz.So we have to design the filter circuit to defend the wave fromdistortion.In the design of the software,we introduce the appliance of theA/D ,TLC2543.In this disquisition,we adopt the newest production inbiomedicine,and use the excellent IC such as the MCU AT89C51,the showmodule EDM1602 produced by the DALIANDONGXIAN.The wholesystem is sententious and trusty.