近年来EMCCD被越来越多地用于天文观测,国内EMCCD相机的研制和观测也在加速。介绍了基于TI的EMCCDTC253相机的数字控制系统及其设计方法。首先对TC253以及模拟信号处理器AD9845B的工作原理及控制要求进行了分析。重点介绍了在QuartusII的开发环境下,使用VHDL语言与FPGA对该图像采集系统的数字控制部分进行分析与设计过程,并给出系统仿真波形图。最后在所设计的硬件电路上进行了测试,给出了关键控制信号的实测波形。通过实测时钟波形与EMCCD器件要求波形的时序比较分析,得出了该实际系统对VHDL程序中信号时序的修正量,从而获得了满意的EMCCD驱动时钟。
The design method and digital control system of EMCCD TC253 camera based on TI are introduced. The opera- tion principle and control demand of the EMCCD TC253 and the analog signal processor AD9845B are analyzed in the paper. The processes of analysis and design for the digital control section of the image acquisition system by VHDL and FPGA are intro- duced in the development environment of QUARTUS II. The simulation waveform diagram is given in this paper. The waveform was tested in the designed hardware circuit. The actual tested waveforms of the critical control signals are obtained by hardware circuit tests. The results show that this modular design can meet the requirement of the control system for the TC253 device. Af- ter some comparison and analysis between the simulating and the testing results, the timing deviation of the clock signals was de- termined through their driving circuits. With this deviation, several lines of the codes for generating the signals timing in the VH- DL program were modified. Consequently the clock waveforms from driving circuits were obtained.