| 摘要 |
PURPOSE:To accurately measure the loss of an optical cable, by uniguely determining the linear approximate expression of a reflected signal wave form between two set points from the coordinates point on the reflected signal wave form between two points by a method of least squares. CONSTITUTION:The reflected signal returned in an optical cable to be measured by reflecting a signal incident to said optical cable from one end thereof is received by a photoelectric conversion part and the converted electric signal is subjected to averaging treatment to display the reflected signal wave form thereof by CRT. To the level difference part of this display, a reference point M is set by a marker and reference points R0 and R1, R2 and R3 are set by markers 23 and 24, 23 and 25 so as to interpose the reference point M therebetween. In this case, the (n) number of coordinats data are selected between reference points R0 and R1 and reference points R2 and R3 and the linear approximate expression of the reflected signal wave form is determined by a method of least squares to uniguely calculate linear lines l, l'. When the level difference amount Y of the reference point M is calculated from the approximate expression, the weld loss of the fiber cable and the loss of a connector are accurately measured on the basis of the linear lines being uniquely determined from the reflected wave form having a large amount of noises. |
