5Ghz Chirp Signal Generator for Broadband FMCW Radar Applications

Abstract

Direct digital synthesis (DDS) is a method of producing an RF analogue waveform which is usually a sine wave. However, there are a limited number of devices capable of producing a high frequency output (of more than 2 GHz). To generate complex waveforms, you ideally require a high-end expensive FPGA board with on-board high speed SerDes transceivers coupled with a DAC. The 'Analog devices' AD916X series is one of the few devices that can output frequencies over 5 GHz. In this paper, we present a low-cost implementation scheme for producing high frequency waveform patterns using Xilinx FPGAs and AD9164, with the minimum of latency. Our pro-posed solution makes use of the Xilinx 7 series and Ultrascale devices, using the high speed SerDes channels over the FMC connector together with the PCIe bus for fast loading of pat-terns. With our proposed solution it is easy to generate and play back complex waveforms, while maintaining a jitter free and low phase noise output. One of the most important application areas that would benefit from our proposed implementation is the generation of high frequency FMCW radar chirps and simulating target responses especially in the upcoming 77GHz frequency range where the baseband can sweep to 4 GHz.