To provide a system which allows for accurate engine timing when a rotary or a cylindrical valve is used to distribute an air/fuel mixture for combustion according to subsonic speed or supersonic speed.

This engine timing input system 400 includes a profile timing disk 160 having a predetermined circumferential edge profile 405 and a frequency wheel 170 at the outer peripheral edge at which a plurality of slots 180 are disposed. The peripheral edge profile 405 comprises one or more elliptic slit portions corresponding to the quantity of combustors 105 which are adopted in a specific PDE (Pulse Detonation Engine) design. The frequency wheel can provide a more accurate representation of valve position by partitioning the valve position into a large number of pulses during each rotation of the rotary or cylindrical valve. The profile disk and the frequency wheel provide a fuel valve timing and an ignition signal in conjunction with the rotating valve when used together with a programmable timing circuit.