基于线阵CCD的模拟前端设计

Analog Front End Design Based on Linear CCD

针对线阵CCD模拟前端电路复杂、成本较高等问题,设计了一种结构简单、价格低廉的模拟前端模块。该模块使用施密特触发反相器作为CCD时序信号的驱动器,可增强输入信号的驱动能力;电压跟随器作为CCD电荷信号的数据缓冲器,使比较完整的电荷信号送入ADC进行采样,保证了图像信息的完整性;同时,电压跟随器还能在CCD电路与ADC采样电路之间搭建有效的阻抗匹配。实验结果表明,使用该模拟前端模块的线阵CCD图像扫描系统可以采集2 292.7 DPI质量的图像,而且架构简单,稳定可靠,具有一定的实用价值。

To solve structural complexity and high cost problems of the traditional linear CCD analog front end circuit,an analog front end with simple structure and low price was designed in the paper. The Schmitt trigger inverter was used as the CCD timing generator,which can enhance the driving ability of input signals. Intact analog signals of the image signal was sent into the ADC by the use of a voltage follower as the data buffer. In addition,the voltage follower can build an effective impedance matching between the CCD circuit and the ADC sampling circuit. The experimental results shows that a CCD image scanning system using the proposed analog front end is able to acquire images with a high quality of 2 292. 7 DPI. Moreover,the structure is simple,stable and reliable,and it has a certain practical value.