An improvement of the controlling algorithm for Taiwan´s time scaling system

Telecommunication Laboratories (TL, Taiwan) developed a new controlling algorithm to improve the short-term and mid-term stability of TL´s time scaling system. The controlling algorithm is used for controlling a micro-phase stepper to constrict its output followed a reference paper clock, Taiwan´s local atomic time scale - TA(TL). The original system used frequently p-control adjustment to keep the system almost synchronized with the reference paper clock. The new algorithm used a derivate control mode to set the long term frequency offset of the micro-phase-stepper, and used a proportional control mode to adjust the daily phase deflection. The new algorithm improve the short-term stability of the system from 1e-13 into 4.6e-14 when the average time = 600 seconds; and the long-term Allan deviation still constrained with paper clock, up to 2e-15 when the average time is more than 7 days