Abstract: A clock distribution apparatus with active phase alignment which makes the incidence of a timing event occur essentially simultaneously at multiple physically remote destinations. The circuit uses traces configured as reflective transmission lines with a matched impedance input. The propagation time of a transmission line is determined by monitoring the current into the transmission line. Variable delays are determined for each transmission line by measuring the actual propagation time and reducing a predetermined maximum delay time by that amount. The variable delay values are stored and used to retard clock edges by the varying amounts so that all clock edges arrive at respective remote destinations at a time equal to the maximum delay time.

Abstract: A clock distribution apparatus with active phase alignment which makes the incidence of a timing event occur essentially simultaneously at multiple physically remote destinations. The circuit uses traces configured as reflective transmission lines with a matched impedance input. The propagation time of a transmission line is determined by monitoring the current into the transmission line. Variable delays are determined for each transmission line by measuring the actual propagation time and reducing a predetermined maximum delay time by that amount. The variable delay values are stored and used to retard clock edges by the varying amounts so that all clock edges arrive at respective remote destinations at a time equal to the maximum delay time.