用于VLBI数字基带转换的多相滤波技术研究

The Study of DBBC Based on Poly-phase Filter Banks and FFT in VLBI

该文阐述了利用低通滤波器和多相滤波器技术实现VLBI数字基带转换的原理,建立了采用多相滤波器与FFT技术的数字基带转换系统的仿真模型;然后对本模型的算法复杂度进行了分析和比较;最后对该模型的正确性进行了仿真实验验证.

With the further development on the Astronomy and deep space exploration, the incremental improvements that are expected on the VLBI is real-time, high sensitivity, reliability and more frequency coverage. VLBI data acquisition backend acts as an important role in VLBI station. Recently, based on the technique of A/D（Analog-to-Digital）, DSP（Digital Signal Processing）, FPGA（Field Programmable Gate Array） and so on, it is practical for middle-frequency signal to be sampled and digital processed directly. DBBC （Digital Base-band Converter） will take place of the analog BBC in VLBI data acquisition backend. In this paper, Full spectrum base-band converted signal model in VLBI has been established. The principle of digital base-band converters based on low-pass filter banks and poly-phase filter banks in VLBI are discussed in details. Mathematical models of these base-band converters are derived, arithmetic operations and complex are analyzed and compared. A simulation model of poly-phase filter banks is designed. All the experimental results show that the model is valid and practical.