Abstract: Optical network for signal transfer from a central station to subscriber stations. The signal to be distributed is split in at least two stages, with the signal being amplified by optical amplifiers. The Erbium Doped Fiber Amplifiers (EDFAs) to be used for this purpose are fed by an optical supply signal. By building up the supply signal from various signals with wavelengths lying closely together, Stimulated Brillouin Scattering (SBS) is avoided. As a result, by utilising centrally supplied EDPAs more splitting stages may be applied, as a result of which many more subscribers may be reached from one signal source than before. The subscribers may utilize inexpensive, low-sensitivity receivers. The optical network is particularly suited to form, in conjunction with a conventional non-optical (twisted-pair) network, a hybrid bi-directional transmission system.

Abstract: Clock recovery circuit for an ATM receive,r that automatically derives the frequency of the source signal which is transmitted by the ATM cells. A subcircuit (3, 4, 5) determines, on the basis of the cell rate, the nominal bit rate of the source signal and generates a clock signal having a frequency which is consistent therewith. A second subcircuit (6, 7, 8, 9, 10) corrects, in proportion to the difference between the nominal bit rate and a mean actual bit rate, the frequency of the clock signal generated by the first subcircuit.