| 摘要 |
<p>The invention is to make so as to reduce as far as possible a detection leak in a case detecting a body having entered into a predetermined range. A pulse sensor having a first reception system and a second reception system is adopted in regard to one transmission system. And, a detection distance of the first reception system is set to about 0.75 [m] for instance. By this, a characteristic of a lowest reception sensitivity of the first reception system becomes a curve Seta. Further, about 0.05 [m] which has been deviated, in regard to the detection distance of the first reception system, by a distance corresponding to a half-wavelength of a wave of a main frequency within a transmission signal to which a band restriction from a transmission system has been applied is set as the detection distance of the second reception system. By this, the characteristic of the lowest reception sensitivity of the second reception system becomes a curve Setb. As a result, a detection of the body existing in distance ranges D2 to D5 becomes possible. The present invention can be applied to the pulse sensor.</p> |
