多抽头EMCCD相机时序控制及像元合并技术

Timing Control and Pixel Merger Technology of Multi-tap EMCCD Camera

摘要:

高速、高灵敏度相机在自适应光学系统中可以对波前误差进行实时测量,为大型地基望远镜提供接近衍射极限的目标图像。多抽头电子倍增电荷耦合器件(EMCCD)相机是自适应光学波前探测的最佳选择之一,基于8抽头的CCD220设计了2000f/s级高速、高精度、多路同步时序发生器,并通过时序控制的方法在CCD器件上实现了多种像元合并,进一步将相机帧频提高到3500f/s(2×2合并)和5700f/s(4×4合并),并能对相机感兴趣区域进行控制。时序发生器的步进精度可达到2.5ns,输出的各路驱动信号的相位抖动可达200ps以下。

Abstract:

The adaptive optical system of a large ground-based telescope needs to use a high-speed and high-sensitivity camera to measure the wavefront error in real time to obtain a target image close to the diffraction limit. The multi-tap electron-multiplying charge coupled device(EMCCD) camera is one of the best choices for adaptive optical wavefront detection. Based on the 8-tap CCD220, a high-speed (2000f/s), high-precision and multi-channel synchronous timing generator is designed. A variety of pixel combinations have been implemented on the device, thus the camera frame rate is increased to 3500f/s (2×2 merge) and 5700f/s (4×4 merge), and the area of interest of the camera can be controlled. The stepping accuracy of the timing generator can reach 2.5ns, and the phase jitter of each driving signal output can reach below 200ps.