EQUIPMENT AND METHOD FOR REMOVING AN UNWANTED PERIODIC NOISE SIGNAL FROM ELECTRIC SIGNALS OBTAINED THROUGH A MEASURING OPERATION

摘要

A method and apparatus for removing a sinusoidal noise signal having constant amplitude and phase from a seismic signal. The noise signal is continuously monitored to detect its phase and zero crossing of the noise signal to generate first and second trigger signals. The trigger signals are used to control the recording of seismic signals resulting from consecutive firings of a seismic source. Then, depending upon the polarity of the seismic source, the recorded signals are either added or subtracted to remove the unwanted noise signal.