Transmission system for periodic signals - includes master clock circuit using two main oscillators and auxiliary oscillators

摘要

The transmission system, for periodic signals, is used in a telephone exchange or data processing network, to supply clock signals to a number of electronic units. It employs a master clock (1), with at least two main oscillators (2, 3) and at least two auxiliary oscillators. The auxiliary oscillators each have phase enslaving means, with the input for the reference signals connected to the output of a respective signal selection circuit (24, 26, 28) for the output signals from the main oscillators (2, 3). The signal selection circuit (24, 26, 28) is controlled by a detector (30, 32, 34) responsive to the correct functioning of the two main oscillators (2, 3).