| 摘要 |
PURPOSE:To decrease the output frequency error attended with the frequency error of a reference oscillator by calculating the frequency division number under a prescribed condition. CONSTITUTION:The output of a reference oscillator 11 is subject to frequency division by a frequency division number mu by the 1st variable frequency divider 7, the phase of the output and that of the output of the 2nd variable frequency divider 3 are compared by a phase comparator 4, the voltage controlled oscillator 6 is controlled by the output and the output of the voltage controlled oscillator 6 is subject to frequency division by a frequency division number nu by the 2nd variable frequency divider 3. K-set of oscillators are provided as the reference oscillator 11 and one of K-set of frequency output is selected by a switch 12. The control circuit 8 uses a value mu smaller than a prescribed value mu0 and decides values mu, nu to select fi in a way of minimizing the error with an outputted frequency fi(nu/mu) and a frequency to be outputted. The error in the output frequency due to the frequency error of the reference oscillator is decreased. |
