Patent ID: 7519113

Claim:
An electronic device having a noise detection function, comprising: a plurality of the noise detection devices; and a position detection device, each of said plurality of noise detection devices comprising: a reference signal generator that generates a reference signal, a Phase Lock Loop (PLL) comprising: a voltage controlled oscillator that controls an output frequency based on a control voltage, and a phase comparator that compares a phase of a signal outputted from the voltage controlled oscillator with a phase of the reference signal and provides an output voltage to be used for obtaining said control voltage and which outputs a signal that is in synchronization with the reference signal from the voltage controlled oscillator; measuring means for measuring a jitter amount from the output signal of said PLL; and judging means for judging a degree of a risk of a malfunction caused by noise interference based on an output of said measuring means, said position detecting device detecting a position in which noise is detected based on an output of said judging means in each of the plurality of noise detection devices, wherein a plurality of the noise detection devices having different noise sensitivity levels are provided; and a noise detection device of high noise sensitivity is placed in a part of a printed circuit board that is susceptible to noise and a noise detection device of low noise sensitivity is placed in a part of the printed circuit board that is resistant to noise so that noise which occurs in the printed circuit board is detected.