Support for MIMO Pre-Equalization in BI-DAC System: An Accurate Frequency Response Obtaining Method

Software Defined Radio (SDR) is widely used in the military, civil aviation and other fields. SDR generates signal bandwidth with limited by Digital-to-Analog Converter (DAC) sampling rate, single DAC performance can hardly satisfy the bandwidth requirement of SDR systems, so multi-DAC parallel technology is proposed. Bandwidth Interleaving DAC (BI-DAC) is a frequency-based multi-DAC parallel technique, which splits the signal by frequency in the digital domain and then restores it in the analog domain, the aliasing error is one of the main errors in BI-DAC system. The aliasing error can be corrected by the Multiple-Input Multiple-Output (MIMO) pre-equalization technique, while the accurate obtaining of the system frequency response matrix is the prerequisite for MIMO pre-equalization. In this paper, we propose a vector estimation method based on amplitude spectral scalar, which can accurately obtain the frequency response of the system. In addition, we verify the effectiveness of the method in this paper through an experiment, the result shows that the accuracy of the system frequency response obtained by this method meets the requirements of the MIMO pre-equalization technique.