【摘要】 非接触眼压检测是通过将压平的物理量信号转变为电信号从而得出最终的眼压,但检测出的信号一般都比较微弱。针对微弱且富含噪声干扰的信号设计出了一个一级降噪放大电路。将最基础的跨阻运放电路进行改进,在反馈回路采用反馈电阻和反馈电容并联的方式可以在低频段产生高通截至点来抑制直流电压失调和相关噪声。并且在非反相端使用RC分压电路来抑制电阻分压器和电源产生的噪声。通过对电路的分析和详细的参数计算得出一个完整的前置放大电路,并分别对电路做了相关的噪声和仿真分析,最终取得了一个稳定且无系统振铃的信号。更多还原

【Abstract】 Non-contact intraocular pressure(IOP) detection is to obtain the final IOP by converting the physical signal of the flattening into electrical signal;however,the detected signal is generally weak. A first-order noise reduction amplifier circuit is designed for weak and noisy signals. The most basic transconductance discharge circuit is improved. The feedback circuit can produce high-pass cut-off point in low frequency band by parallel connection of feedback resistor and feedback capacitor to suppress DC voltage offset and related noise. RC voltage divider circuit is used to suppress the noise produced by resistor voltage divider and power supply at the non-inverted end. Through the analysis of the circuit and detailed parameter calculation,a complete preamplifier circuit is obtained;and the related noise and simulation analysis of the circuit are made respectively. Finally,a stable signal without system ringing is obtained.更多还原