| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a signal detection device capable of suppressing erroneous detection of noises and detecting ripple signals correctly. <P>SOLUTION: This signal detection device 10 includes an active band-pass filter 11 having a variable pass band between a first cut-off frequency and a second cut-off frequency which is lower than the first cut-off frequency, a signal detection portion 12 which detects signals from an output of the filter 11, and a control process portion 13 which performs the optimization process of the pass band using a detection result of the signal detection portion 12. The control process portion 13 performs the process of expanding the pass band by increasing the first cut-off frequency or by decreasing the second cut-off frequency according to the relation of the magnitude of the frequencies of noise signals and ripple signals, so that the ripple signals are contained in the pass band in the optimization process. <P>COPYRIGHT: (C)2008,JPO&INPIT |
