An apparatus and corresponding method for outputting a protocol pulse based on a speed signal representing speed of an object. The apparatus includes a zero-crossing circuit, and a delay circuit. The zero-crossing circuit is configured to output the protocol pulse at a zero-crossing of the speed signal. The delay circuit is coupled to the output of the zero-crossing circuit and configured to delay the protocol pulse. A first edge of the protocol pulse is asynchronous with a clock, and a second edge of the protocol pulse is synchronous with the clock.