Design Of Signal Acquisition Circuit For Wireless Passive Intraocular Pressure Sensor

Intraocular pressure is one of the key physiological indicators of the human visual system.Pathological increase in intraocular pressure is the most important indicator for the diagnosis,treatment and monitoring of glaucoma diseases.In order to solve the cumbersome,complicated and non-continuous problems of intraocular pressure measurement in clinical diagnosis,the related institutions at home and abroad are devoted to the research of an LC wireless passive intraocular pressure sensor,but the research on the wireless acquisition system of sensor signals is relatively lagging.This paper focuses on LC variable inductance wireless passive intraocular pressure sensor,research and design a signal wireless detection circuit,the main research work includes:1)Analyze the coupled electrical model between the wireless signal acquisition circuit and the sensor circuit,explore the change of the impedance parameters of the intraocular pressure sensor at different frequencies,and determine the wireless acquisition of the LC wireless passive intraocular pressure sensor signal based on the real part measurement of the impedance.method.2)According to the real part detection theory of impedance,design the wireless acquisition circuit of the intraocular pressure sensor signal,complete the design of the frequency sweep signal generation,the frequency sweep signal amplification,the mixing filter,the data acquisition and the wireless transceiver,the device selection and simulation,The PCB layout and optimization design of key signals is completed,and the circuit system function debugging is completed.3)Write the upper and lower machine software of the system,and design the “programcontrolled triangular continuous frequency sweep” control algorithm,which effectively improves the sweep frequency range,sweep frequency accuracy and sweep frequency efficiency,so that the circuit can be extended to LC wireless without multiple parameters.Application of source intraocular pressure sensor.4)Build a circuit function test platform,and complete the measurement accuracy and stability experiment of the circuit system under the condition of plane sample and artificial eyeball pressure.The results show that the circuit's resonant frequency measurement accuracy is ±0.06 MHz and the repeatability is 0.0165.The comprehensive measurement of intraocular pressure is ±1.2mmHg,which meets the application requirements of ±3mmHg.