A method for controlling an engine having both an electronically controlled inlet device, such as an electronic throttle unite, and an electronically controlled outlet device, such as a variable cam timing system is disclosed. An embodiment of the present invention may permit a less power consuming portion of an integrated circuit to operate at a relatively higher average clock rate than a more power consuming portion operating at a relatively lower clock rate, by adjusting the duration of the cycles of the higher frequency clock. The quadrature mirror filter receives a speech signal, divides the speech signal into an enhancement band speech signal and a base band speech signal, and outputs the enhancement band speech signal and the base band speech signal. and the cross-sectional area S, and the inner diameter Di mm satisfy:ES\u2061Di\u2264600.