The speech has whistle-like noises. We can clearly see that the whistle-like noise looks different from other parts of the voice. I searched Google for removing hissing (I don't know the correct term for this type of noise), and a YouTube video said low-pass filter is the solution. But that did not work; It just made the whistle-like noise as if it coming over a telephone line. Is it possible to remove or reduce the noise?
If what I am saying is unclear, here is an example YouTube video for this type of noise. It is not the sound of the waves above, but shows the same type of noise.
PS: I have not tried this, but the method I thought of is like this. To me, the waves look almost the same before and after the noise. So, I could choose the last "normal" wave and repeat it over the noise interval, programmatically.