Ultrasonic Measurement Technology Based On FPGA

Ultrasonic imaging is mainly used for borehole logging and casing imaging,observing the dip direction of the wall cracks and other parameters in open hole and detecting casing damage and corrosion in cased hole closed.With the help of image processing technology echo imaging information,its Instrument emits ultrasonic waves and collects the echo amplitude and time,directly reflects the characteristics of the wall and on the sleeve.This paper focuses on the measurement circuit ultrasonic imaging logging tool to study and proposes a new method for the measurement circuit and carry on the corresponding software simulation analysis.For transmission circuit,proposes a new method for two PWM pulse modulated waveform generation FPGA,the two signals with each other to generate a pulse width and height waveform that can be controlled to drive transducer.At mean while,for echo analysis circuit,put forward digital echo analysis system based on FPGA,the system passes the echo after AD conversion into the FPGA internal firstly,through parallel-serial conversion unit input it to comparator to record the first echo arrival time,under storage unit continuous compare new input waveform data,records the maximum echo amplitude in a acquisition cycle.Finally,for communication circuit,the FPGA designs serial communication interface through which serial communicate with PC,using RS485 serial communications chip,FPGA will upload the data to the host computer is stored and displayed in the serial debugging software interface.This interface can also be used with downhole communication with other units.In order to experiment the above research,draws the PCB and debugs the circuits and analyzes the results.The results show that this method can effectively motivate transducer and receive the return wave,the echo system can accurately determine the maximum peak and the echo time of the input waveform,it helps to take a step forward to design a complete ultrasonic imaging acquisition system.