A digital single sideband modulator for a digital radio frequency memory

Abstract

The purpose of this study is to verify that a digital single sideband modulator can he incorporated into a Digital Radio Frequency Memory (DRFM). The single sideband modulator is designed to use digital multiplying integrated circuits to produce the frequency shift rather than analog mixers. The circuit also employs a digital Hilbert transform filter to shift the phase of the incoming signal by 90 degrees. The circuit was tested with simulated S-band radar signals ranging from 3.012 to 3.038 GHz. The circuit, running in double sideband mode, proved its ability to shift the frequencies of the radar signals by frequencies in the range of-25 to +25 kHz. All the spurious outputs of the system were found to be more than 28 dB below the carrier.

The hardware platform design for DRFM system

“…Digital Radio Frequency Memories (DRFMs) form the significant building block in radar countermeasure systems, the basic idea of the DRFM can be found in reference [1],and the modern application example in radar countermeasure systems and radar signal simulator is widely stated as in [2][3][4],with the development of the integrated circuits(IC) technique, especially the participating of the field programmable gate array(FPGA), the hardware platform architecture has been greatly changed compared with the former states in [5,6]. Besides the development of the capacity of the hardware platform, the new design idea motivated by the concept of Software Radio (SOW) are stated as in [7].…”