FREQUENCY MEASUREMENT DEVICE, FREQUENCY MEASUREMENT METHOD AND OSCILLATION TYPE SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a technique which can widen a section where frequency can be properly measured without making frequency conversion adjustable even while using a constitution hardly being large size.;SOLUTION: A heterodyne unit 2 executes rise conversion forming a sum frequency component fs+fr with respect to a measured frequency fs and down conversion forming a differential frequency component |fs-fr|. If fs is too high to perform measurement with a first measuring instrument A, the differential frequency component |fs-fr| passes through a band pass filter 3 and if fs is too low to perform measurement with the first measuring instrument A, the sum frequency component fs+fr passes through the band pass filter 3 and proper measurement for each component can be performed with a second measuring instrument B. A processor 4 specifies which one of the sum frequency component fs+fr and the differential frequency component |fs-fr| passes through the band pass filter 3 from a measurement result of the first measuring instrument A and performs calculation of corresponding inverse conversion on a frequency represented by a measurement value of the second measuring instrument B in order to calculate fs.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2016,JPO&INPIT