Tian Xia Peilin Song Hao Zheng Characterizing the VCO jitter due to the digital simultaneous switching noise. 70-73 2005 conf/glvlsi/2005 ACM Great Lakes Symposium on VLSI http://doi.acm.org/10.1145/1057661.1057680 db/conf/glvlsi/glvlsi2005.html#XiaSZ05