Real time continuous Doppler filtering is used to calculate the spectrum of the input signal to detect the presence of random disturbances and properly isolate them. For continuous input data this can be done in two ways. In first method the data is divided into blocks and FIT is performed on each block to evaluate its spectral content. The resolution of this method is 'N' where 'N' is the order of the input block. This method cannot pinpoint the exact sample time of occurrence of disturbance.