| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic flowmeter capable of controlling properly the gain of an amplifier regardless of the quantity of impurities such as air bubbles included in a fluid, executing flow measurement with a high S/N ratio even to the change in kind or temperature of the fluid, and executing stably always accurate flow measurement. SOLUTION: This flowmeter is constituted so that waveform data including at least a peak value in a received signal are digitally converted by an analog-digital converter 9 and preserved in a memory 11, and that a processor 10 selects the peak value in the case where impurities such as air bubbles or solid powder are not included in the fluid, as a selected peak value from among the peak values preserved in the memory at each prescribed time interval, compares the selected peak value with a peak set value set beforehand in the processor, transmits a control signal to a gain control terminal of an amplifier 5 based on the comparison result, and controls so that the peak value in an output signal of the amplifier becomes roughly in the same degree as the peak set value. COPYRIGHT: (C)2006,JPO&NCIPI
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