The paper presents the development and validation of an automatic digital modulation classifier based on a waveform digitizer architecture. The proposed automatic digital modulation classifier can be used for signal recognition in the next generation telecommunication systems, characterized by a flexible and dynamic management of the radio spectrum. It has been implemented on a PC architecture, connected with two different types of waveform digitizers. The experimental validation has been carried out by means of actual telecommunication signals, even in presence of narrowband and wideband interference. (C) 2011 Elsevier Ltd. All rights reserved.