An optically repeated SCM system with subcarrier frequency conversion

We propose use of an optically repeated SCM system with subcarrier frequenc y conversion for video monitoring, with the aim of realizing benefits in tw o areas: first, cost-effectiveness and simple design by using standardized transmission equipment and reducing preparation for lasing wavelength selec tion of light sources; and second, to increase the transmission length and number of terminals. In order to characterize transmission performance, we simulated CNR affected by optical beat interference derived from the simult aneous detection of multiple optical signals, and by noise accumulation in electric amplifiers. We also simulated composite distortions generated at a light source and a receiver in an optical repeater where, for the first ti me, we used a simulation of composite distortions depending on subcarrier f requencies in semiconductor lasers, which we previously proposed. To practi cally evaluate those simulations, an SCM system having two optical repeater s with subcarrier frequency conversion was set up. We confirmed that the si mulated CNR and composite distortions are in good agreement with measured r esults. As we confirmed the validity of those simulations, we derived limit s of transmission length, number of terminals, and number of optical repeat s by evaluating CNR and composite distortions. We also demonstrate those re sults. (C) 2000 Scripta Technica.