Call the original voice signal mtlb, and carry out FFT transform on it, and remove the FFT transform value with the amplitude less than 10, and finally reconstruct the voice signal. (It is required to have the spectrograms of four voice signals in the same graphic window for comparison: 1, the original voice signal; 2.FFT transform; 3. Remove the FFT transform value whose amplitude is less than 10; 4. Reconstruct speech signal)

Program code:

Load mtlb

Subplots (2, 2,1); Drawing (mtlb);

x = FFT(mtlb)； Subplots (2, 2, 2); plot(ABS(x))； % Fourier transform

y = x；

y(ABS(x)& lt； 10)=0; Subplots (2, 2, 3); plot(ABS(y))； & Remove FFT whose amplitude is less than 10.

x = IFFT(y)； Subplots (2, 2, 4); Figure (X)% Inverse Fourier Transform Reconstruction Signal