Elimination of Electromagnetic Interference in Communication Channels by Using Spread Spectrum Techniques

This work demonstrates in a theoretical manner how to free certain bandwidths for low frequency communication systems, in an electromagnetically polluted environment by canceling spectral lines of a present disturbance signal. In many cases electromagnetic interference (EMI) is system-intrinsic and the designers have influence on some of its parameters. In case of a combination of switched mode power converters and narrowband communication systems in the same system this paper exhibits how to parametrize spread spectrum clocking (SSC) for the switching frequency of the power converter and possible data rates for a communication system. The authors show a big performance improvement of the system using spread spectrum clocking in comparison to a system with a fixed switching frequency. In integrated circuit design, the use of a single oscillator for the switched mode power supply as well as for the carrier signal in communication systems offers new possibilities in saving chip area and in a possible reduction of the quality of the power distribution network, resulting in less filter components.