Designed of Automatic Frequency Tracking System for Ultrasound Based on FPGA

The resonant frequency drift can be widely found in the application of ultrasonic transducer, which would reduce the work efficiency and destroy circuit components. In order to solve this problem, an automatic frequency tracking system based on FPGA is developed. The system makes use of fast Fourier transform (FFT) combined with fuzzy proportional-integral-derivative (PID) algorithm. Then, a frequency-tracking strategy is proposed to catch the optimal working frequency. The upper computer software is used to control and monitor the whole system, which is more convenient for various application scenarios. It is proven that the tracking of resonant frequency of the ultrasonic transducer can be achieved quickly and accurately. Furthermore, the main advantage of the design system is miniature, versatility and high stability. Finally, the effectiveness of proposed system is validated by an experimental example.