A new acoustic field analysis, based on the Huygens principles, is given for an elastic surface acoustic wave convolver, made by using a focused transducer on a YZ-LiNbO3piezoelectric crystal. In the acoustic field analysis, a new slowness function approximation is suggested for the anisotropy of the medium, instead of the conventional parabolic slowness function. The acoustic field analysis obtained by using this function is compared to the other analysis techniques and the results are discussed.