PROCÉDÉ DE COMMANDE DE BOUCLE VERROUILLÉE EN PHASE À FRÉQUENCE À DEMI-DÉBIT NUMÉRIQUE ET BOUCLE VERROUILLÉE EN PHASE

摘要

A method for controlling a digital fractional frequency-division phase-locked loop and a phase-locked loop are disclosed. The phase-locked loop includes a control apparatus, a TDC, a DLF, a DCO, a DIV, and an SDM. The control apparatus performs delay processing on an active edge of a reference clock according to a frequency control word and a frequency division control word to obtain a delayed reference clock; and sends the delayed reference clock to the TDC so that the TDC performs phase discrimination processing on the delayed reference clock and a feedback clock. A control apparatus added to a phase-locked loop may perform delay processing on a reference clock according to a current frequency control word and a current frequency division control word, so that a feedback clock and a delayed reference clock have approximate active edges corresponding time. In this way, the TDC only needs to process phase discrimination signals within a relatively small time domain input range. This greatly reduces design difficulty of the TDC and lowers a requirement on a resolution of the TDC, and makes design of the TDC simple and free, thereby ensuring convenience, ease, and efficiency in design of a phase-locked loop.