Circuit arrangement for generating an AC ringing signal

摘要

In order to generate ringing signals, telephone systems require low-frequency AC voltage sources. Patent ... shows a circuit arrangement for generating an AC ringing signal of this type which requires only a DC voltage which differs from the earth or the reference potential, only a very low component cost being incurred through the use of the entire permitted ringing voltage distortion. This circuit arrangement is extended according to the invention in such a way that a switchover between two required system voltages is possible in the simplest fashion. With an extremely low component cost, expensive storage of AC ringing voltage circuits of different sizes is no longer required. <IMAGE>