| 摘要 |
<P>PROBLEM TO BE SOLVED: To determine whether there is a risk of actually causing erroneous operation of a system in noise detection. <P>SOLUTION: The noise detector performing noise detection using the output from a phase comparator in a PLL comprises a reference signal generator, a voltage controlled oscillator for controlling the output frequency by an input voltage, and a phase comparator for comparing the phase between the reference signal and the output signal from the voltage controlled oscillator. The noise detector is further provided with a PLL for outputting a signal synchronized with the reference signal from the voltage controlled oscillator, and a first measurement means for measuring the output from the phase comparator of the PLL. The phase comparator outputs a signal based on the phase difference between the reference signal and the output from the voltage controlled oscillator. The phase difference reflects the effect of noise on the PLL and the effect of the PLL on the noise resistance in addition to the characteristics of noise itself, e.g. the peak value or frequency component of noise, and the risk of actually causing erroneous operation of the system can be determined. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
