Method for synchronizing acoustic asynchronous serial signals while drilling

A method for synchronizing acoustic asynchronous serial signals while drilling, comprising the following steps:

• connecting a transmitting terminal to a receiving master control board through data lines R+ and R, wherein the transmitting terminal comprises a plurality of transmitting boards,
• S1:
• configuring, using a micro-control unit (MCU) of the receiving master control board, parameters for the plurality of transmitting boards through a driver chip, and sequentially returning, using the plurality of transmitting boards, a first command to the receiving master control board after receiving the configured parameters;
• S2:
• broadcasting, by the MCU of the receiving master control board, a second command for exciting a sound source to the plurality of transmitting boards using the driving chip, and changing a configuration of a pin of the MCU that corresponds to R+ from a serial communication mode to a universal input port mode, and starting a rising edge interrupt function of the pin corresponding to R+ so as to be ready to acquire a first rising edge of a signal in R+ when the plurality of transmitting boards in the transmitting terminal returns the first command to the pin corresponding to R+,
• S3, when the plurality of transmitting boards successfully receive the second command, acquiring the first rising edge of the signal in R+ by the plurality of transmitting boards;
• S4, returning, by one of the plurality of transmitting boards, a first command to the receiving master control board by utilizing a parallel processing performance of a field-programmable gate array (FPGA);
• S5, stopping acquiring the rising edge of the signal in R+, starting timing, and implementing monopole emission or quadrupole emission according to the received configured parameters after a time period T1 so as to achieve different emission modes and to maintain signal synchronization of the plurality of transmitting boards;
• S6, reconfiguring the pin corresponding to R+ to be in a serial communication mode so as to be ready for a following communication, starting timing, and sending a third command for starting to acquire an acoustic signal to a data acquisition circuit after a time period T2;
• and
• S7, acquiring, by the data acquisition circuit, data with a certain length according to a sampling rate with a certain frequency when a time period ΔT=T2−T1 has passed from the start of sending the acoustic signal by the sound source.