There is provided a distortion canceling circuit for reducing an unbalance between a higher and a lower 3rd order distortion at frequencies of and, respectively, the distortions being generated by an amplifier which amplifies an input signal having at least two frequency components, i. The dimples on the ball have a cross-sectional profiles formed by a catenary curve. The present invention also provides processes for the preparation of the compounds of formula I. Initiating the call generates called party information.