PHASE-SENSITIVE DEMODULATION Tae-eui, Kim
; 10Hz Sinusoid (Tx = 0.1s) ; High Freq. Signal (Tx = 0.02s) X(t)X(t) c(t) XOXO -X O s 0.1s0.05s0.1s Phase-sensitive Demodulation
Phase-sensitive Demodulation
Phase-sensitive Demodulation With Freq. 50Hz
< MATLAB PLOT WITH HIGH MAGNITUDE > Phase-sensitive Demodulation With Freq. 1000Hz
Given x(t) c(t) = y(t), find x(t) Phase-sensitive Demodulation XLPF
Phase Demodulation After LPF Phase-sensitive Demodulation
Capacitive Sensor – Problem 9 (a) Change of distance Metal plate A B L ; Capacitive is dependent on changing distance between chest and metal plate
A B Capacitive Sensor – Problem 9 (b)
Capacitive Sensor – Problem 9 (c) XLPF
Air ABC P1P1 P2P2 Atmospheric pressure X1X1 X2X2 Chamber rigid Diaphragm One is increased, The other is decreased At the same amount How to express by using equation from the sensor in order to analyze it is crucial (when ) ABC Goal is to measure “ “ Capacitive Sensor – Problem 10 (a)
A AC (Capacitor) C D B
Capacitive Sensor – Problem 10 (a)
ConstantxHigh Freq. Something we would like to measure Constant
Capacitive Sensor – Problem 10 (b) ConstantUnit less
Capacitive Sensor – Problem 10 (c)