G.729 is a CS-ACELP-based  standard for 8kbit/s speech compression and is defined by the ITU. In the G.729 encoding phase, the open-loop pitch T op is estimated for each frame to reduce the computation required to search for the best adaptive codebook delay. However, > 25% CPU time is required for the open-loop pitch analysis. The weighted delta-LSP(WD-LSP) function is employed here to reduce the computation required for open-loop pitch analysis. An 81% saving is made in the computation of T op . A total computational saving of 21% for the encoding phase is achieved and the speech quality still sounds good (MOS = 3.5).