Abstract:The effect of Digital BaseBand Converter (DBBC) sub-channel delay on bandwidth synthesis precision is analyzed under the condition of the consistent receiving system channel delay in order to improve the accuracy of bandwidth synthesis. Through a theoretical derivation, it is for the first time to discover that the sub-channel delay could induce “phase step” phenomenon among the different sub-channels in the group delay measurement of a single station. And in the delay difference measurement of different stations, the “phase step” phenomenon could occur when the frequency differences of different stations’ corresponding sub-channel Local Oscillator (LO) are different. The “phase step” could deteriorate the precision of bandwidth synthesis. The impact domain of the sub-channel delay is discussed for different DBBCs, suggesting that the “phase step” can be eliminated by a sub-channel delay compensation. The simulation results show that the sub-channel delay compensation can effectively remove the “phase step” and the precision of bandwidth synthesis can be improved by at least one order of magnitude or more.
姜坤, 王元钦, 马宏, 焦义文, 廉昕. 甚长基线干涉测量数字基带转换器子通道时延影响分析[J]. 电子与信息学报, 2014, 36(6): 1509-1514.
Jiang Kun, Wang Yuan-Qin, Ma Hong, Jiao Yi-Wen, Lian Xin. Impact Analysis of the Sub-channel Delay in Very Long Baseline Interferometry Digital Baseband Converter. , 2014, 36(6): 1509-1514.