针对极谱法测量痕量离子浓度时信号微弱、噪声强难以有效析取的问题,设计了一种基于有源滤波的极谱信号析取电路。极谱电流检测电路由I-V转换器和程控放大电路构成,并设计具有贝塞尔响应特点的高阶有源低通滤波电路用以抑制噪声。实验结果表明,滤波效果好,极谱波峰重复性误差小于0.5%。 Aiming at the problem that the signal is weak when the trace ion concentration is measured by polarography and the noise is hard to be extracted efficiently, a polarographic signal extraction circuit based on active filter is designed. Polarographic current detection circuit consists of I-V converter and programmable amplifier circuit, and design with Bessel response characteristics of high-order active low-pass filter circuit to suppress noise. Experimental results show that the filtering effect is good, and the reproducibility error of polarographic peak is less than 0.5%.