Digitally-Assisted Compensation Technique for Timing Skew in ATE Systems

Abstract

This paper describes timing skew adjustment techniquesin ATE systems (such as for timing skew compensation inn interleaved ADC system and an SSB signal generation system) using a digital filter with novel linear phase condition proposed in our ITC2010 paper. A conventional linear phase digital filter is an FIR filter with coefficients of odd- or even -- symmetry and whose group delay NTs/2 where N is the number of the Fir filter taps and Ts is the sampling period, its group delay time resolution is Ts/2. We have generalized the linear phase condition, and with our novel linear phase condition, the group delay time resolution can be arbitrary small, and the coefficients are not necessarily odd- or even-symmetric. In this paper we discuss several practical issues for applying our digital filter to timing skew compensation in ATE systems, such as truncation of the infinite number of taps, techniques of using window and DC gain adjustment. We also compare our digital filter with the fractional delay digital filter.