| 摘要 |
<p>PURPOSE:To detect a metalic body in an object of measurement by detecting an output generated in a balance-type reception coil disposed in a magnetic field formed by an excitation coil, when the metal substance passes between the excitation coil and the reception coil. CONSTITUTION:Data on a temperature measured by a temperature sensor 1 are converted into an electric signal and inputted to CPU 9 through an A/D converter 8. Frozen food 12 after measurement is made to pass through a search coil 13 constructed of an excitation coil 2 and a reception coil 3. A detection output generated in the reception coil 3 by the frozen food 12 in the search coil 13 is inputted also to a detector 6 through a high-frequency amplifier 5, a product effect of the frozen food is removed therefrom consequently, and the output is inputted to an amplifier 7. In the amplifier 7, a gain is controlled by a control signal from the CPU 9, and an output thereof is taken outside as a metal detection signal through the A/D converter 8 and the CPU 9.</p> |
