| Sonar as underwater target detection and positioning equipment,one of the important components of the transducer array.Due to the production process and other reasons,the amplitude and phase level between each array element is difficult to be consistent.Therefore,in order to improve the receiving accuracy of the array,a set of transducer amplitude conformance testing system is designed in this paper.The main contents of the dissertation include the overall system design,hardware platform construction and software compilation.According to its function,the hardware platform is divided into five parts: integrated control module,signal generation module,signal conditioning module,channel switching module and signal acquisition module.The integrated control module adopts the DSP+FPGA architecture,because DSP has floating point operation ability,and FPGA foot resources are abundant,which reserve space for the upgrade of the system.The signal conditioning module uses the program control magnification mode to ensure that the gain of each channel is the same,thus increasing the consistency between the channels.As the system can test 128 channels at most,this paper uses 64 sets of relay to form a channel module,which not only completes the expansion of test channel,but also ensures the consistency of amplitude and phase between channels.The system uses AD9244 as the analog digital conversion core chip of the signal acquisition module.The device supports high speed sampling rate and can realize the acquisition of high frequency signal.At the same time,the display control software that matches with it is designed by using VC++.After the test system is started,the software of the host computer will automatically check it,and the modules in the system can complete the corresponding function under the control of the software.When the user needs to configure only some parameters,the system can automate the test process and generate the Word document by using the test results.The system can produce a specified frequency signal,which is driven by an external amplifier to promote the transmission of a transmitter.In the end,the data is uploaded to the upper computer.After the computer is analyzed and processed,the consistency of the amplitude and phase between the channels is displayed on the interface.The whole system is tested in laboratory environment.During the frequency band of 20 kHz to 200 kHz.The performance is stable,the amplitude consistency is less than + 1dB,and the phase congruency is less than + 3 degrees,which accords with the expected design requirements. |
