Noise impaired echo path modelling using chaotic coded speech

An experimental evaluation of an echo path modelling device is reported for chaotically coded speech telephony circuits. Results show that uncoded speech is ineffective in driving the model when noise-to-echo ratios exceed approximately -30 dB and thus invalidates live measurements. The chaotic modulation, however, increased the transmitted signal energy and allowed adaptation for far end noise conditions exceeding 30 dBs higher than that of the uncoded case. Furthermore, for the practical range of noise conditions considered, it is shown that the proposed coding scheme results in a faster convergence rate than the upper bound established for the noiseless uncoded case