Abstract: This design first introduces the elementary knowledge of MATLAB software, Has an preliminary understanding to its main application aspect. Next introduced the high step system related knowledge. Has established one kind high step numeral phase-lock link system design based on the DPLL. This system design proposed one kind based on the PI algorithm three steps numerals phase-lock link, application the related knowledge of control theory as: The stability, the open-loop system time domain frequency range characteristic, the system simulation and so on, carries on the analysis to the phase-lock link system, has done a better improvement design to it compared to the former system . The theoretical analysis and the simulation experiment indicated that t change the proportional-plus-integral control parameter may adjustment phase-lock link system phase-lock speed and the stability conveniently.
Key words: The high step system ; Simulation; DPLL; MATLAB;