Principle and application of a new test signal to determine the transfer characteristics of telecommunication systems

Measuring procedures yielding defined and reproducible results are required to determine transfer functions for tests and registrations. On the one hand, such a test signal allowing the determination of the transfer characteristics of these systems must simulate voice properties adequately. On the other hand, such a signal must be determined exactly so that not only the transfer function in different operating modes can be measured but also the switching and switch-off times and the behaviour of such systems in duplex operation, the echo return loss and especially the temporal behaviour of echo cancelling equipment. In order to meet all these requirements, a special test signal, called the composite source signal, has been defined