| 摘要 |
PURPOSE:To realize reduction for the noise, the structure measurements and the cost by constituting the PLL circuit using the voltage control oscillator featuring the oscillation frequency of M- times as high as the final output frequency and then giving M step-division to the output of the voltage control oscillator to obtain the final output. CONSTITUTION:The N1 step-division is given via fixed divider 2 to the output of reference oscillatol 1 featuring the oscillation frequency of M-times as high as the output frequency and then supplied to phase comparator 3. While the output of voltage control oscillator MC010 is mixed with the output of reference oscillator 6 via mixer 7 and undergoes N2 step-division at variable divider 4 through band pass filter 5 which draws out only the difference frequency component to be supplied to comparator 3 where the phase comparison is given with the reference signal given from cscillator 1 with N1 step-division applied. Then the error signal is supplied to VC010 via loop filter 8 and LPF9 to be used for the phase synchronization of VC010. The output of VC010 undergoes M step-division through step-divider 12 to be delivered through terminal 11. In this constitution, the final output phase noise is reduced down to 1/M the output noise of VC010, thus ensuring easy reduction of the noise along with use of the low-noise crystal oscillator to oscillator 1. |
