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.