Description:

The invention relates to a method and device for measuring the rotation speed, in a highly disturbing medium of a hydrogenerator. According to the invention, the method consists in the digital determination of an input signal (Sin) by means of some counters (NV1, NV2, ..., NVk) with sequential functioning, with sequential discrimination of the digital amplitude values (DA1, DA2, ..., DAk) or the variation speed (DV1, DV2, ..., DVk) in relation to a reference value imposed by the measured system and the application of some weighed mean (MP1, MP2, ..., MPk) wherein the weighing factors are determined off-line according to the transfer function of the measured system, excited with a Dirac impulse or a weighing function determined by the mathematical weight of the measured system so that the measurement accuracy is maximum in the desired performance field. According to the invention, the device for applying the method consists of a hysteresis shaper circuit (FH), whose impulses are counted by k counter (NV1, NV2, ..., NVk) and an impulse generator (GKI) which generates k impulses decoded by means of a decoder (DEC) in k start-up signals for those counting k (NV1, NV2, ..., NVk), a real time generator (GTR) which determines each value of the rotation speed of a hydro generator by relating the signal generated by the hysteresis shaper (FH) to the real time generator (GTR), a number of k blocks (DA1, DA2, ..., DAk) for eliminating the digital values whose amplitude is higher than a reference value determined by the measured system and the transmission of this signal of k blocks (MP1, MP2, ..., MPk) of balanced intermediation, where the balancing coefficients are determined off-line depending on the transfer function of the measured system, excited with an impulse.