| 摘要 |
<p>PURPOSE:To enable regulation of sensitivity from outside by feeding pulse signal of which duty ratio is variable and of which frequency is higher than low frequency disturbance component from outside, in order to intermit oscillating operation of radiating part of electromagnetic wave. CONSTITUTION:A discriminating device of the most appropriate sensitivity outputs pulse signal SP for sensitivity regulation to an open collector, for instance. An intermitting part 8 of oscillation operation is fed the signal SP from outside via a pulse signal input terminal 7 for sensitivity regulation of an in/out connector 7, and then, according to the pulse signal, oscillation operation of an electromagnetic wave radiating part 2 is intermitted. When the signal SP is L, a transistor 8b is switched on, and also a GaAsFET 2a is switched on to oscillate the radiating part 2. When the signal turns into H, the transistor 8b is switched off and also the FET 2a is switched off to cease oscillation of the radiating part 2. Therefore, the radiating part 2 intermits the oscillation operation according to duty ratio of the signal SP. Also, at a level comparison part 5, signal level of low frequency disturbance which is required for outputting of the signal SP is varied. By this procedure, regulation of sensor sensitivity can be conducted from outside.</p> |
