Fpga-based Frame Transfer Ccd Camera System

With the development of space technology, the astronomical observation has been gradually extended from ground observation to space observation. Concurrently, the CCD camera, an astronomical observation imaging end instrument, has already entered the outer space orbit. The high-energy radiation in the space environment will damage the CCD chip which is used for space observation. The transfer efficiency, dark current, noise, and other major performance of CCD chip will adversely affected. Thomson/Atmel/e2v's TH7899M is a CCD chip suitable for space applications; therefore, it is a significant work to evaluate the chip. In order to assist a NAOC research project(i.e. Evaluation of Radiation Damage of CCD Chip for Space Astronomical Observation), we have commenced to design and research a frame transfer CCD camera based on FPGA, referred to as RDCCD for short.According to the general requirements of RDCCD, this paper introduces the design and research of the analog circuit, ADC and the control module based on FPGA. First it presents selections for the key chips such as CCD, FPGA and ADC, and details on the basic structure of the circuit and design philosophy of RDCCD in two aspects of hardware and software. In the hardware the system contains a CCD peripheral circuit, an Analog Front End, a clock driver, a power supply, and in the software there are some VHDL programs and their firmware implemented in FPGA(i.e. a clock timing generator) according to the time sequence of the CCD driving clocks, ADC sampling clocks and data transferring clocks. Then the simulation and testing results for some key circuits and VHDL programs are presented and analyzed. At last several images taken by the CCD Camera and some testing results are shown. Usually the sicientific CCDs operate in a low temperature so as to reduce the dark current and attain better performance, thus this paper also give a concise expression on vacuumizing and refrigeration experiments for a small dewar.