Seismic amplifier means and method
 The seismic amplifier includes an amplifying circuit which amplifies an analog signal to provide an amplified analog signal. The amplified analog signal is converted to digital signals. A controlled network connected to the amplifier circuit controls the gain of the amplifier circuit in a manner so that the gain for a current seismic operation, except for an initial seismic operation, is determined during the next previous vibration seismic operation. 
Texaco Inc.
G
G01V
inventional
Herbert J. Donald L.
Meyer Howlett