Error vector-based measurement method for radiofrequency digital transmitter troubleshooting

The rapid growth of modern telecommunications systems has created the need to get new test equipment and measurement techniques operational in a very short time. Performance assessment of radiofrequency digital transmitters, with special regard to the troubleshooting of their I/Q modulation section, calls for new, reliable, and time-effective measurement methods because those based on the analysis of constellation diagrams, currently supported by major manufacturers, show some intrinsic limitations. To overcome these limitations, a new measurement method based on the use of the error vector is proposed in the paper. It works properly when only one or two I/Q impairments are significant, and assures comparable accuracy and reduced measurement time with respect to other solutions already presented in the literature. Besides describing the fundamental steps and basic relations characterizing the proposed method, the paper gives details of the extended experimental activity carried out on actual telecommunication signals in order to assess the performance.