天文学进展2011，Vol.29Issue(2)：207-217,11.
我国新一代VLBI数字基带转换器研制进展
The Progress of Modern Chinese Data Acquisition System
摘要
Abstract
With the development of software radio technologies, especially the using of programmable components, more and more equipments can be digitalized for its convenience, efficiency and reliability.The Chinese Data Acquisition System (CDAS) independently designed by Shanghai Astronomical Observatory of CAS is a digitalized base band covertor for VLBI, which can take the place of traditional analogy base band covertor. It consists of two parts. One is responsible for AGC (Automatic Gain Control) and anti-aiiasing, which keeps the optimal quantization level for the ADC following. The other is responsible for data acquisition and process, which quantifies 512 MHz wideband signal by a high speed ADC and splits the broadband up to 32 baseband after calculating by FPGAs in real time. It also can be connected with either MK4 or MK5 recorder.This article describes the principle of phase-shifting method applied, framework composed and experiment results obtained by CDAS. Compared to the traditional analog base-band converter,the experiment results obtained in terms of band-pass characteristics, SNR (signal-noise ratio) and delay dispersion for example, show the performance improvement of CDAS.CDAS is not only smaller in size, but also higher performance. It will serve for geodesy,astrometry, and spacecraft orbit determination.关键词
VLBI/射频/中频/基带/下变频/DDSKey words
VLBI/ radio/ IF/ base-band/ down-convert/ DDS分类
天文与地球科学引用本文复制引用
朱人杰,薛祝和,凌权宝,罗近涛,陈岚,张秀忠,韦文仁,项英,李斌,吴亚军,王锦清,赵融冰,舒逢春..我国新一代VLBI数字基带转换器研制进展[J].天文学进展,2011,29(2):207-217,11.基金项目
探月工程二期科研(0824361002) （0824361002）
