| 摘要 |
PROBLEM TO BE SOLVED: To reduce the influence of an interference signal and to extract a sub-signal with excellent sensitivity by comparing the level of a first output signal and the level of a second output signal and switching and selecting the first output signal and the second output signal, based on this comparison result. SOLUTION: By a first multiplication means 120, the sub-component signal of an FM detection signal is multiplied by a sub-carrier wave synchronizing signal, and by a second multiplication means 130, the sub-signal is multiplied by the inversion signal of the sub-carrier wave synchronizing signal. By a signal generation means 140, the first sub-signal based on an upper side wave component and the second sub-signal based on a lower side wave component are generated from each output signal from the first multiplication means 120 and the second multiplication means 130. The output levels of the first and second generated sub-signals are compared by a level comparison detection means 150 and the sub-signal which is high in the output level is switched and selected by a signal selection means 160. As a result, the sub-signal with excellent sensitivity can be extracted. |
