A method for generating a series of output signals represented by a series of measurement signals which is particularly useful in the compensation for jatter, missing spurious pulses or plates when applied to the processing of signals from a speed probe monitoring the speed of a rotating bladed shaft. The method includes the steps of predicting a value for a first measurement signal from a historical measurement signal value, generating a first output signal from the predicted value of the first measurement signal; comparing the measurement signal to its predicted value, and: if the measurement signal is within a predetermined range of acceptable values, using the first measurement signal to predict a value for a second measurement signal; if the measurement signal is outside the pre-determined range of acceptable values, using the first predicted value to predict a second measurement signal, and generating a second output signal from the predicted value of the second measurement signal.