Pink noise whitening method for pitch synchronous LPC analysis

We present a new noise whitening method for pitch synchronous LPC analysis under pink noise circumstances. First, we utilize a rectangular window to extract two frames whose shifting interval is a full pitch period. Then we perform a subtraction operation between the two frames to obtain a new noise signal which is considered to be not corrupted by the voiced speech signal. The obtained new noise signal can be used to design a new prediction whitening filter. The new whitening filter not only whitens the pink noise signal, but also can keep the vocal tract and formant natures of voiced speech signal. Utilizing the whitened signal, we can improve the pitch synchronous addition and subtraction (PSAS) method under pink noise circumstances. We discuss the properties of the whitened signal and PSAS method. Experimental results indicate the effectiveness of the proposed method.