Method and apparatus for signal reflection removal, such as echo cancellation, is described. Some configurations may comprise two circular trackpads, driven by the player’s thumbs, which may be clickable, allowing the entire surface to act as a button. The cathode employs a cathode active material containing a compound of the olivinic structure represented by the general formula LixFe1-yMyPO4, where M is at least one selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.