Improvement And Implementation Of Impedance Analysis And Testing Device

As a carrier of underwater acoustic equipment transmitter and receiver, transducer needs to be constantly measured, including of its impedance, phase angle, etc, for preparing the matching circuit, calculating electro-acoustic conversion efficiency. Impedance analyzer has a wide frequency range, high precision, but it has large volume, high price and other issues. It is also difficulty to carry. Therefore, this paper designed a small, impedance testing device which is easy to carry, and can be applied to measure a variety of underwater acoustic equipment transducers.First, the background and significance of the paper is introduced; The second section describes the development of resistance test apparatus. Then according to the impedance measuring principle of underwater acoustic transducer, hardware circuits and software programs are designed. With OMAP_L138 + FPGA as the core of the hardware circuits portion, the FPGA minimum system circuit, a signal generating circuit, two-channel signal acquisition circuit, data storage circuit, data read circuit, the touch screen serial communication circuit and power supply circuit are completed. In order to improve the accuracy of measurement, the self-test calibration circuit is increased. Software programs portion uses Verilog language to describe the generation of DDS signals, serial communication, decoding of AD chips and other logic circuits; and writes the ADC data collection, SD card data storage, network port data read and other procedures by using C language. Data processing and impedance characteristic curve describing are implemented on the MATLAB software.Eventually, each part of the whole impedance testing device is tested. Then the standard resistance and vnderwater acoustic transducer are measured. The obtained data which is measured is compared with that of the impedance analyzer, analyzed and corrected errors.Experimental data indicate that this device reaches the design requirements. The measurement equipment used for underwater acoustic transducers is realized.