There is disclosed a signal having a predefined quality criterion for use with a communication systems, a method of and a system for generating such a signal, a method of testing the operation of a communication system using such a signal and a (tele)communication system arranged for operation such a method. The method for generating the signal having a predefined quality the steps of: --representing a first signal comprising a plurality of frequency components each having spectral amplitude phase properties, and--processing the represented signal by arranging its spectral amplitude properties, and--processing the represented signal by arranging its spectral amplitude properties in accordance with the predefined quality criterion.