CABLE FOR MEASUREMENT AND METHOD FOR MEASURING THE SAME

PROBLEM TO BE SOLVED: To improve the measuring accuracy of a measuring instrument by producing a plurality of states by providing a calibrator which calibrates the measuring instrument to a cable for measurement and a change-over switch to the calibrator. SOLUTION: A cable for measurement is provided with a calibrator 7 united with a change- over switch in one body at one end of a coaxial cable 6 and a signal terminal 8 and a grounding terminal 9 at the front end of the calibrator 7. The calibration of a measuring instrument is performed by rotating a rotary switch in such a state that the signal terminal 8 and grounding terminal 9 are respectively connected to the measuring spot of a circuit board to be measured and the ground of a circuit board. First calibration is performed while the measuring instrument is kept in an opened state by bringing an open terminal 17 into contact with one end 15 of the grounding terminal 9 by rotating the upper section 10 of the calibrator 7. Then second calibration is performed while the measuring instrument is kept in a short- circuiting state by bringing a short-circuiting terminal 18 into contact with the end 15 of a grounding line by similarly rotating the upper section 10 of the calibrator 7. Finally, third calibration is performed while the measuring instrument is kept in a loaded state by bringing a loading terminal 19 into contact with the end 15 by rotating the upper section 10. After completing the first to third calibration, actual measurement is performed by bringing a measuring terminal 20 into contact with the end 15.