The Research Of Time Measurement Circuit Based On FPGA

Time measurement circuit based on FPGA is an important component of the X-ray pulsar navigation, X-ray pulses were collected as the trigger signal for this moment of time, the precision of the time 1 ns, range of 99 years. Has the characteristics of high precision and wide range. The time measurement circuit is the whole hardware design pattern based on FPGA, adopt the way of combination of coarse and fine time to carry on the design. Rough time use of gray code counter for years, months, days, hours, minutes, seconds. Fine time using Xilinx IODELAY primitives provided by the company to main frequency under the design of the time. Finally reach the requirements of the project 1 ns precision time measurement circuit and the USB chip CY7C68013A time measurement circuit data transfer to PC.Time measurement circuit of this article is based on the Chinese academy of sciences, xi’an light machine cooperation project of the X-ray pulsar navigation, the final testing phase are completed in xi’an light machine. Time measurement circuit is X-ray pulsar navigation back-end circuit is an important part of, front end circuit developed by xi’an light machine. All the present stage of research is based on the test on the ground simulation system. The X-ray pulsar navigation ground simulation system includes:X-ray generator, vacuum system, MCP detector, the front plastic amplifying circuit, time measurement circuit and USB transmission. The time measurement circuit and USB transmission is the research content of this article.Paper adopts the integration of the X-ray pulsar ground simulation system testing, test results transmitted to the PC through USB pulse contour reduction. The pulse profile after reduction and in NASA downloaded the pulsar contour similarity is 95.38%. To,reach the project requirements. But pulsar navigation to this method of real-time poor, is not easy in the real space navigation. Pulsar-based navigation system, Linux has become the main object of study to the next stage in accordance with the requirements of real-time, so you can put the entire time measuring circuitand the subsequent reduction pulses are integrated into the Linux system to facilitate real-time processing of data to complete the accurate time measurement circuit navigation work. In the last chapter of the thesis describes the development board ZedBoard describing its work steps and possible problems and solutions, and ported to Linux system development board ZedBoard completed coordination ARM and FPGA. To conduct follow-up work has played a important role.