Evolving an adaptive digital filter

One important feature of signal processing is coping with noise. In a non-adaptive filter, characteristics of the filter may be refined to remove noise. One method of achieving this is to use evolution to decide the filter characteristics. However, if the noise level is sufficient or the input signal is not of the required type for the output signal required, then a satisfactory output signal may not be achievable. To be able to achieve the required output signal for a wide range of input signals and noise, it is desirable to be able to adjust both the characteristics and the type of the filter. In this way the resulting filter may be said to be an adaptive filter. In this paper we propose an on-chip solution for an adaptive digital filter using an on-chip evolvable hardware method. We highlight a challenge within evolvable hardware for adaptive designs and that is to find efficient ways in which sufficient genetic material will be available to the evolution process. This problem appears when the evolution process is automatically restarted so as to adapt to a change in the environment.