Abstract: A tachometer and angular progression measuring system for a rotary device of the type including a pickup for producing a pulse each time the rotary device has rotated a given angle which includes a source of first pulses of a first frequency synchronized to the pulses from the pickup, means for counting the number of first pulses occurring between two successive pickup pulses, a source of second pulses of a higher frequency than the first pulses, and a means for producing output pulses whose period between two successive pulses correspond to a number of periods between successive second pulses depending on the number of first pulses counted by the counting means.