| 摘要 |
<p>An analog phase-locked loop and a method of realizing the hold function thereof are provided, belonging to technical field of communication. The analog phase-locked loop comprises: a phase detector, a loop filter and a VCO, and includes a hold circuit connected in series between the loop filter and the VCO as well. The hold circuit collects a control voltage from the output terminal of the loop filter, and processes it correspondingly to supply an input signal to the VCO. The corresponding method is: the phase detector comparing the phase of a received reference signal to that of a feedback signal to output an error signal to the loop filter; the loop filter outputting a control voltage corresponding to the said error signal; the holding circuit collecting and processing the said control voltage to supply the input signal to the VCO. In the present invention, when a reference source is lost or deteriorated, the output of the whole phase-locked loop cannot be pulled deviated, that is to say the phase-locked loop has a "hold" function, so as to improve the reliability of the output of phase-locked loop.</p> |
