| 摘要 |
PURPOSE:To perform a reliable detection with an excellent S/N, by a method wherein, through storing in a memory of a given gain and phase adjusting amount against temperature of a material to be measured, a reference phase and an amplifying gain are adjusted. CONSTITUTION:A required gain and phase adjusting amount against a temperature to be measured are previously written in a memory 8 for exclusive use in a program enabling reading. For example, if the temperature of the material to be measured is high, a detecting output decreases, and thereby a gain adjusting amount required for holding it in a constant manner, a phase of a detecting output changes, and with this a required phase of a reference wave in a phase detection changes, whereby a necessary correction amount is written. Thus, the memory 8 is accessed by the output of a temperature sensor S, a required adjusting amount at a corresponding temperature is read out from the memory, and the result is inputted to a variable attenuator 5 and a variable phase device 9 to control it. This enables a detecting output to be brought into a constant manner and permits to perform a detection at an optimum phase. |
