유효 비트수 확장을 이용한 대전상관기의 상관 정밀도개선에 관한 연구

Abstract

In this paper, we propose the effective bit expansion of FFT module for improving the accuracy of correlation result of the Daejeon correlator. The Daejeon correlator based on FPGA was implemented in order to fast data processing with the fixed-point of FFT operation. In correlation result, however, the phenomenon of phase concentration to 0 degree was appeared in lower frequency area of bandwidth due to lack of operational bit. This phenomenon has an affect on the accuracy of correlation result by introducing the effect of data loss because of excluding phase concentration during analysis of observed radio source. In order to improving the accuracy of correlation result we carried out the simulation by expanding bit-number than 16-bit operation of previous FFT module within given resource limits of FPGA. Through the simulation results, the effective bit number for FFT module within used FPGA resource limits is able to expand, and we confirmed that the operational 20-bit of FFT module is effective for improving accuracy of correlation result by comparing with experimental result.