Notice of Retraction The Design of Cased Hole Formation Resistivity Logging of Preamplifier Circuits

Notice of Retraction After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles. We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper. The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org. In view of the signals of the cased hole formation resistivity logging which is extremely low, the voltage is nanometer. The amplifier technology is the key of logging technology of formation resistivity through casing. In this paper, which contains the design of signal conditioning circuits, the pre-amplifier utilizes the method of reducing power supply noise and select the low-noise amplifier. In order to achieve the performance and requirements of the circuit, the pre-amplifier make use of virtual GND and some of the denoising ways such as multi-level filtering respectively.