| 摘要 |
<P>PROBLEM TO BE SOLVED: To surely detect high-frequency noise. <P>SOLUTION: A noise measuring device includes: an A/D converter 3 which samples a measurement target signal Si and outputs data Da; a filter section 4 which outputs data Db representing a signal component contained in a passband including a frequency of high-frequency noise to be superimposed on the measurement target signal Si; an effective value calculator 5 which outputs an effective value De of the signal component contained in the passband on the basis of the data Db; a trigger generator 8 which outputs a trigger signal St when the effective value De is equal to or more than a threshold value Dth; a buffer memory 7 which stores the data Da as storage data Dc just for a previously specified number; and an FFT arithmetic section 9 which reads the data Dc from the buffer memory 7 synchronously with output timing of the trigger signal St, performs Fourier transform processing on the data Dc, arithmetically operates and outputs the high-frequency noise superimposed on the measurement target signal Si during a specific term including a time point of superimposing the high-frequency noise on the measurement target signal Si. <P>COPYRIGHT: (C)2012,JPO&INPIT |
