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This example demonstrates phase-sensitive demodulation using MATLAB for medical instrumentation. It includes MATLAB source code and diagrams.
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MEDICAL INSTRUMENTATION.Second Homework 동서의료공학과 2005200444 정 진 웅
1. Phase-sensitive Demodulation Example1. e X
Matlab sourse of example1. >> t1=0:0.001:0.1; >> x_0=2; >> y1=x_0*sin(2*pi*10*t1); >> y2=sin(2*pi*50*t1); >> y3=y1.*y2; >> plot(t1,y1); >> plot(t1,y2); >> plot(t1,y3);
Matlab sourse of example2. >> t2=0:0.0001:0.1; >> y4=x_0*sin(2*pi*10*t2); >> y5=sin(2*pi*1000*t2); >> y6=y4.*y5; >> plot(t2,y4); >> plot(t2,y5); >> plot(t2,y6);
? Diagram of demodulation If y(t) = x(t) * c2(t)= x(t) * sin2(2π*fct) 2sin2(2π*fct) = 1-cos(4π*fct) So, sin2(2π*fct)=1/2(1-cos(4π*fct) ) y(t) = x(t) * c2(t)= x(t) * 1/2(1-cos(2π*fct) ) = 1/2x(t) - x*1/2*cos(2π*fct) = 0
2. Capacitive Sensor (a) step1 chest Applied HR=60bpm → f=1Hz
(b) step2 Analyzing this circuit, On next slide, try sketch the Vo(t) using matlab
3. Problem 10 P1 P2 sol) rigid rigid x1 x2 when P1=P2,, C1 = C2 diaphragm C A B C1 C2 our goal is to measure ‘|P1– P2|’
constant constant
LPF 10Hz