A transponder module of a system for measurement of a race time includes a time base in a microcontroller, which is activated upon receipt of a low-frequency electromagnetic field signal from a transmission antenna of a measuring system which is disposed at the level of a line of passage. The microcontroller, once woken up, is capable of measuring several successive intensities of the captured electromagnetic field in order to reconstruct a curve of the electromagnetic field and to determine a crossing time on the line of passage of the transponder module with the activated time base thereof in order to transmit, to a decoder unit of the measuring system, a signal of the result of the time of crossing determined by the microcontroller.