| 摘要 |
<p>PURPOSE:To measure moisture exactly by converting the reflected light for three kinds of IR wavelengths photoelectrically, controlling the gains of the 1st and the 2nd signals, adding the same with a variable resistor and dividing the result thereof by the signal obtd. by the gain control of the 3rd signal. CONSTITUTION:Filters 71, 72, 73 having different wavelengths are provided concentrically on a rotary disc 6, and the light from a light source 4 is irradiated through a condenser lens 5, the filters and a reflecting mirror 8 to an object 3 to be measured. The reflected light is condensed to a photoelectric transducer 10 from a concave mirror 9. A signal separating and rectifying part 12 operated by a synchronizing signal generator 13 separates and rectifiers the signals of the respective wavelengths and outputs the same. The 1st and the 2nd signals pass through a gain control circuit 17 and are added by an adder via a variable resistor. The added signal is divided by the 3rd signal past the circuit 17 in a divider 23 and is linearized with a logarithmic conversion circuit 25. Moisture is thus measured always exactly irrespectively of the kind of the object to be measured by setting only the gain and the weight of the variable resistor properly.</p> |
