| 摘要 |
PURPOSE:To measure the jitter stably with high accuracy while following up the frequency variation of a high frequency signal to be measured even if the frequency variation is high. CONSTITUTION:The output signal from a voltage controlled crystal oscillator 11 is multiplied by M through a multiplying circuit 13 and used for down converting the frequency of an input signal to the mixer circuit 15 in a frequency conversion circuit 14. The converted output is fed, along with the output signal from the voltage controlled crystal oscillator 11, to a phase frequency comparator 17. A loop filter 20 receives the error signal and locks the phase of output signal from the frequency conversion circuit 14 to that of output signal from the oscillator 11 through loop control. The jitter component of the signal to be measured, having the phase variable at higher frequency than the loop band, is outputted from a jitter detection filter 18 through a second branch circuit 19. |
