A circuit is designed with a reference circuit (200) for generating a reference signal. The reference signal determines a reference period. A delay circuit (208, 212, 216) responsive to the reference signal produces a delay signal. A control circuit (248, 254, 258, 260, 262) responsive to the delay signal produces a control signal. The delay circuit emulates the speed of an integrated circuit for the reference period. Control signals from the control circuit compensate the integrated circuit performance for measured circuit speed variations.