低通濾波器具有截止頻率；它可以去除實際信號的高次項諧波，但是當雜訊的頻率低於諧波頻率時此舉會同時會產生於低迴轉率SR（Slew Rate）的失真。衰減雜訊的過程中也對原始訊號造成變化，進而影響數據處理的後續步驟。 然而基於雜訊的分佈特徵，本文提出了一種方式是藉由擷取輸入信號的高低峰值進而產生對應的上部包絡和下部包絡，藉由取其上部包絡和下部包絡的平均值以減少高斯雜訊。設計的快速響應濾波器，沒有截止頻率；因此實際信號的高次諧波保持不變。也因此它可以立即響應輸入信號的變化，並保留實際信號的完整性。此外，它只有很小的相位延遲。 而迴轉率、相位延遲和頻率響應皆可從Multisim 13.0的模擬結果中得到的證實，本文所提之濾波器可保留原始訊號的高次項諧波、實現6.34v⁄μs的迴轉速率，相位差幾乎為零。而藉由實體測試 Vin 3Vpp之Gaussian Noise，經此雜訊濾波器後Vout 為120mVpp。可將雜訊抑制為原訊號之4%。;In general, the low-pass filter has a cut-off frequency; it can remove the higher order harmonics of the actual signal, but when the frequency of the noise is below the harmonic frequency, the result of square wave will have in distortion of the low slew rate. The process of dampening noise also changes the original signal, which in turn affects the subsequent steps of data processing. However, based on the distribution characteristics of noise, this paper proposes a method to obtain the corresponding upper envelope and lower envelope by extracting the high and low peaks of the input signal, by taking the average of the upper envelope and the lower envelope to reduce the Gaussian noise The design of the fast response filter, there is no cutoff frequency; so the actual signal of the harmonics remain unchanged. And therefore it can immediately respond to changes in the input signal and retain the integrity of the actual signal. In addition, it has only a small phase delay. The rotation rate, phase delay and frequency response can be confirmed from the simulation results of Multisim 13.0. The filter mentioned in this paper can preserve the harmonic of the original signal and achieve the rotation rate of 6.34v⁄μs and phase shift almost zero. The physical test V_in：3Vpp Gaussian Noise, after the noise filter V_out：120mVpp. Noise can be suppressed to 4% of the original signal.
