| 摘要 |
PROBLEM TO BE SOLVED: To provide a tone signal detector capable of judging the presence/ absence of the amplitude modulation of tone signals. SOLUTION: A frequency selection means 100 eliminates noise components other than the tone signals of a detection object and a signal strength calculation means 101 calculates signal strength to the output of the frequency selection means 100. The signal strength is compared with a prescribed threshold value in a comparison means 102 and the presence/absence of the amplitude modulation is judged based on the frequency of generating the change point of the compared result in a judgement means 105. By configuring in such a manner, the presence/absence of the amplitude modulation of the tone signals is judged. |
