Method and circuit for data intercommunication of downhole device and ground

The invention discloses a method and a circuit for data intercommunication of a downhole device and the ground. A power supply data bus is utilized to transmit digital signals. A sending and receiving signal selection switch ensures that only one of a sending circuit and a receiving circuit can be hung on the power supply data bus at any time so as to solve the problem that the signals can be greatly attenuated by a resistance-capacitance element in a system circuit. Two-digital binary coding is utilized to replace the existing Manchester encoding to improve the communication efficiency. According to the method and circuit, the technical scheme of the two-digit binary coding is adopted, and the carrier level amplitude can be reduced to 1/2 to 1/4 of the existing level amplitude. The method and the circuit can ensure that the attenuation amplitude of a level within the length range of 10000 M is less than 20% of the initial value of a carrier, the data can be sent continuously without extra recovery time withi