Implementation of a multi-waveband, high-precision, wideband waveform generator based on DDWS for antenna channel characteristics test

In practical radar systems, amplitude and phase distortion exists in antenna channels, which has a bad effect on subsequent signal processing. So, waveform generator is needed to launch signals covering radar waveband to make a channel test. Ensuring accuracy and bandwidth of the waveform generator is a fundamental requirement. Accordingly, this paper proposed a full flow of wideband waveform generation, including hardware design, parameter selection and pre-distortion correction. Direct digital waveform synthesize (DDWS) is done in the first, second, or third Nyquist region without analog frequency conversion, ensuring the quality of the waveform. And pre-distortion measures are taken to correct the waveform reconstruction error. The waveform generator designed in this paper has been successfully applied in a digital array radar (DAR) system, which can generate 500MHz bandwidth LFM signal, covering multiple waveband including 0.65 GHz-1.15 GHz, 1.25 GHz-1.75 GHz, 1.85 GHz-2.35 GHz, 2.45 GHz-2.95 GHz.