| 摘要 |
PROBLEM TO BE SOLVED: To measure the volumetric difference of industrially mass produced objects of same type and shape accurately under dried state using one object as a reference object. SOLUTION: An acoustic volume meter comprises a measuring container 2, a reference container 1, a sound source speaker 6 for providing these two containers with an alternating volumetric variation differentially, a detection channel 5 interconnecting these two containers, a first microphone 10 for detecting the sound pressure in the detection channel 5, and a second microphone 11 for detecting the sound pressure in the reference container 1. Output from the first microphone 10 is rectified synchronously with the output from the second microphone 11 and the volumetric difference between two objects is measured based on the magnitude of the synchronous rectification signal when a reference object 3 is placed in the measuring container 2 and when an object to be measured is placed therein. If the volume of the reference object 3 is known, volume of the object to be measured can be determined by adding it to a measured volumetric difference.
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