SDRAM在大视场TDICCD空间相机中的应用

该文针对大视场空间相机中需要缓存的图像数据量大的问题，对高速大容量存储器SDRAM控制技术进行了研究。首先，说明了大视场空间相机中图像数据缓存的需要，根据CCD图像数据和图像缓存工作特点，提出了基于行使能和刷新操作驱动和基于仲裁策略的SDRAM控制器。然后，为了提高图像数据缓存可靠性，针对缓存小数据量场合，提出了(6,8)纠错算法，针对缓存大数据场合提出了RS(143,127)和RS(142,126)码纠错算法。最后，在XX-X空间多光谱相机样机的成像系统上进行了试验验证。实验结果表明:两种控制器工作频率能够达到131 MHz，正常工作时，行使能驱动控制器存取速度达到127.08 MBps，仲裁策略控制器存取速度达到139.788 MBps，两种纠错算法在507 B/row内可以纠正32 b错误。基本满足空间相机中的稳定可靠、高效率的缓存图像数据要求。

Application of SDRAM to the Large Field of View TDICCD Space Camera

In order to resolve the problem of images buffering with huge amount of data quantum in large field TDICCD space camera,the control technology of SDRAM which is a high-speed and large capacity data memory is studied.First,the paper explains the image buffering demand in large field TDICCD space camera,and a SDRAM controller using line enabling driving and a SDRAM controller using arbitration policy are proposed based on the characteristics of CCD image data and that of image buffer.Then,In order to improve reliability for data buffering,a(6,8) error correction algorithm is proposed for the small data situation,and a error correction algorithm of RS(143,127) and RS(142,126) code are proposed for the large data situation.Finally,the verification experiments to CCD imaging system in the prototype machine of XX-X space multi-spectral camera are carried out.The experiments results show that the working frequenc of the two proposed controllers is able to reached 131 MHz.When the system works steadily,the data access speed of line driving controller is 127.08 MBps,and that of arbitration controller is 139.788 MBps.The two proposed error correction algorithms are able to correct 32 b errors in 507 B/row.It can satisfy the space camera data buffering requirements of non-contact,real time and rapid speed.