| 摘要 |
PURPOSE:To make it possible to accurately judge whether or not frequency characteristics is appropriate by inputting the first test signal having a specified frequency into a multimode fiber, and measuring the frequency characteristic value of the multimode fiber at this time. CONSTITUTION:An oscillator 1 is set in a reference frequency signal oscillating mode, and this frequency is transduced into an optical signal. The signal is inputted into a multimode fiber 3 to be measured. The value of a selecting level meter 5 at this time is read. Then, the oscillator 1 is set in an (f) (3dB) frequency oscillating mode. The signal is transduced into an optical signal which is in turn inputted into the fiber 3. The value of the meter 5 at this time is read out. The difference between this value and the value of the meter 5 when the reference frequency signal is inputted is measured. Thus, the frequency characteristic value when the (f) (3dB) frequency signal is inputted into the fiber 3 is measured. Then, the oscillator 1 is set in an (f) (3dB/2) frequency signal oscillating mode. The signal is transduced into an optical signal which is in turn inputted into the fiber 3. The value of the meter 5 at this time is read. The characteristic value is obtained from the difference between this value and the value when the reference frequency is inputted is obtained. |
