| 摘要 |
PROBLEM TO BE SOLVED: To improve electric field strength sensitivity in SAP signal detection, by preventing misdetection of a SAP signal at weak electric field. SOLUTION: A signal detection apparatus comprises: a SAP detection circuit 3 which outputs a voltage corresponding to a level of a SAP signal; a noise detection circuit 6 which outputs a voltage corresponding to the level of a noise component; a SAP signal detection comparator 4, in which a reference bias can be changed according to the level of a SIF signal when that level is reduced, and which discriminates the presence/absence of a SAP signal, on the basis of the reference bias; a noise detection comparator 8 which discriminates presence/absence of noise components; and a SAP detecting signal generation circuit 9 which outputs a signal, indicating absence of a SAP signal uniformly when the noise detection comparator 8 discriminates presence of noise. COPYRIGHT: (C)2006,JPO&NCIPI
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