Wideband digital fractional time delay waveform generation method based on polynomial fitting

Abstract

Beamforming of wideband signals requires time delay, while traditional time delay methods are complicated and consume a lot of hardware resources. In this letter, a digital beamforming method that can be applied to any wideband signal is proposed. Taking the NLFM signal as an example, this letter studies the generation of digital fractional time delay waveform: the time delay is divided into integer time delay and fractional time delay, and then the fitted exponential polynomial is used to express the time domain phase function of the wideband NLFM signal, and finally fractional delay waveforms can be generated in DDS directly by extracting the parameters. The simulation experiment shows that each array unit produces a wideband time delay beam, the transmitting beam is pointed correctly, the method is easy to calculate and the hardware requirement is not high. It can be applied to any signals whose time domain phase function can be explicitly expressed.