Efficient coding of LSP parameters using split matrix quantisation

This paper presents a new and efficient LPC quantisation scheme called split matrix quantisation (SMQ). The proposed method can be viewed as an extension of the conventional split vector quantisation process. It operates over N consecutive LPC frames and effectively divides a p×N LSP matrix into K submatrices which are then vector quantised independently. SMQ exploits the interframe redundancy that exists between consecutive sets of LSP coefficients and achieves “transparent” quantisation at 900 bits/sec. “High quality” LSP quantisation can be easily obtained at 750 bits/sec. These bit rates are based in a 20 msec LPC analysis frame size. Furthermore, SMQ is characterised by relatively low complexity and low storage requirements