AC-coupling and 1/f noise effects on baseband OFDM signals

The effect of AC-coupling and 1/f noise on baseband orthogonal frequency-division multiplexing (OFDM) signals is investigated. A system model that employs features of the packet format of existing wireless communication standards is used. The model assumes sampling and frequency-estimation errors at the receiver, and also imperfect channel-response estimation. The error vector magnitude (EVM) is selected as the performance evaluation criterion due to the simplicity in its evaluation, and because it allows for an easier comparison with the standards specifications. Simulation results are presented along with analytical expressions for the EVM, which provide system-design guidelines. Finally, simulation results are used to observe the intersymbol interference that is introduced as the AC-coupling filter impulse response exceeds the guard interval of the OFDM symbols