| 摘要 |
PURPOSE:To execute measurement with accuracy without being influenced by an oscillating output drift of an oscillator and a detection efficiency drift of a microwave detector by calculating a moisture content from the phase rotation quantity of a microwave. CONSTITUTION:A microwave sent out of an oscillator 1 is divided into two by a coupler 2, and becomes a measuring microwave and a local oscillating microwave. The local oscillating microwave concerned is divided into two equal parts by the first magic T3, and thereafter, passes through the first and the second waveguides 4a, 4b, respectively, and is inputted alternately to a mixer 8 through a changeover switch 5. The measuring microwave is led to a measuring part 7, projected to an object to be measured 6 and attenuated, also the phase is rotated, etc. in accordance with the moisture content, and thereafter it is inputted to the mixer 8 as what is called a measuring signal. When the changeover switch 5 is switched, output voltage is obtained from diodes 9a, 9a', respectively. As for an output of a differential amplifier 10, in an operating part 12 for receiving it through a sample holding circuit information corresponding to the contained moisture quantity of the object 6 to be measured, namely, the amplitude and phase are obtained. |
