An FPGA-based Direct Sampling and Digital Processing System for Wideband and Narrowband Radar Signal

Abstract

This paper designs an integrated wideband and narrowband radar signal direct sampling and digital processing system based on FPGA. The system comprises a VPX case, a main board, a direct sampling board, a fiber board. It makes direct sampling of 1.8GHz-3.0GHz echo waves, with 3.2GHz sampling rate. The wideband and narrowband echo waves share the same ADC channel. After ADC sampling, both of wideband and narrowband data are exported to a mix-free digital quadrature demodulation module in FPGA. The narrowband data will be further processed by digital frequency down conversion. The wideband data will be further processed by digital de-chirp operation, with parallel DDS structure and multi-level decimation filters. Data rate of both the wideband and narrowband data after processing is decreased obviously. The designed sampling system cut down the analog radar signal processing operation, and decreases signal distortion. Besides, it integrated the reception, sampling and processing of wideband and narrowband signal, simplified the structure of radar system.