In recent decades, many papers describing communication systems based on chaotic signals have been published. However, their performance under non ideal conditions needs further investigation. This work evaluates the performance in terms of Bit Error Rate (BER) of a binary communication system, based on chaotic synchronization, when white gaussian noise is added to the transmitted signal. Furthermore, we propose an encoding function that allows controlling the trade-off between how apparent is the message in the transmitted chaotic signal and BER performance.