PURPOSE: To make it possible to change freely various transmission parameters by providing a regulator circuit for desired attenuation and band-limitation of an electric signal from a signal source and then by modulating a light emitting source by its electric output.
CONSTITUTION: Measuring instrument 1 has signal generator 3 and its pulse signal S1 is inputted to regulator circuit 4. Regulator circuit 4 provides the desired attenuation and band limitation of this input electric signal and light modulation of light emitting diode 7 is carried out by electric signal S2 led out from the circuit 4, which is converted into corresponding photo signal S3. Further, photo signal S3 is inputted to mode converter 9, which performs regulation into the same mode as the transmission mode of an optical fiber cable, so that a photo signal under the same influences as various influences caused by a random optical fiber cable can be obtained in an extremely-easy manner.
IFUKURO SADAO
MORI MASAKAZU
