摘要

Software defined radio (SDR) and cognitive radio have become the development trend for military or civilian radio stations. This paper analyzes the digital to analog (DAC) system based on software defined radio applications. The measurement procedure and calibration technique for hybrid signal system are described in detail. In order to maximize the utilization of the image spectrum and achieve better performance for communication, the sub-Nyquist rate DAC system with different construction modes is introduced. The two-phase holding reconstruction mode utilizes higher order image spectrum by adjusting duty cycle of the two phases. This technique based on SRD has the merit of lower power consumption and higher efficiency for communication system.