Spectral postfilter design based on LSP transformation
H. Tasaki, Koichi Shiraki, Keiji Tomita, Shinji Takahashi · 2002
A new spectral postfilter that has high flexibility of design is proposed. In this method, two LSP (line spectrum pair) transformation blocks compute ARMA filter coefficients for the postfilter. The characteristics of the proposed postfilter can be flexibly designed in the frequency domain, because an effect of LSP transformation can be estimated in the frequency domain. As examples of design, an approximation to a conventional LPC-based postfilter, enhancement in selected frequency bands, and a suitable design for a tandem coding are demonstrated.