Abstract: This study is addressed to improving the quality of the signal of the ANFIS (Adaptive-Network-based Fuzzy Inference System) reducing the level of fluctuations in the output due to periodical disturbances. The fuzzy filter computes the disturbances as periodic signals with two components, one at high frequency and other at low frequency. The filter was incorporated in the layer 0 and it can be applied iteratively to effectively reduce heavy noise.