the present invention relates in general to the field of generation of precise electrical signals , in particular , to a technique for providing accurate delays of signals using a controllable delay line , and is applicable to the areas of high speed communication and memory testing equipment . according to the present invention , an auxiliary reference channel having a delay line which is identical to the main delay line is incorporated into vernier silicon die to allow automatic adjustment of the delay in the main delay line using a reference periodical signal applied to the auxiliary delay line .