Design Of Signal Conditioning And Acquisition System Based On PXI Bus

Projectiles need to consider many technical indicators when running inside guns,such as running speed,acceleration,etc.These parameters are of great significance to the performance of guns.With the continuous development of the level of national defense military technology,more stringent technical requirements have been put on the accuracy of the measurement of projectile movement speed and other parameters in the projectile velocity measurement project,,At present,the commonly used method at home and abroad is the microwave radar interferometry technology,but in practice,due to the influence of the test environment and other factors,the collected signal energy is weak,resulting in the failure to accurately obtain the parameters such as the speed of the inner ballistic projectile.In view of the current practical problems,this thesis analyzes the characteristics of the Doppler signal of the internal ballistic projectile and designs the microwave radar signal conditioning and acquisition system based on the PXI bus.It has very important engineering application value for the measurement of the parameters of the internal ballistic projectile.In the hardware development part,the paper analyzes the existing data of the project and finds that the target signal is superimposed on a low-frequency vibration signal.Therefore,in the front-end signal conditioning module,a filter is designed to filter the low-frequency signal and noise,and the conditioning circuit With the automatic gain control function,the signal amplitude is automatically controlled to achieve the purpose of improving signal quality;in the acquisition of memory modules,PCI9052 is used as the interface chip,and FPGA is used as the local controller to design the AD data acquisition and DDR3 data buffer as one High-speed large-capacity acquisition storage hardware circuit,the system acquisition rate of 50 MSPS,the depth of the cache to 2Gb,focusing on the details of the acquisition memory module design principles and specific implementation;In addition,the use of FPGA digital clock manager(DCM)to generate variable frequency The clock allows the system to perform test tasks in different situations at a flexible collection rate.In the software development part,the thesis analyzes the current PXI bus device driver program and decides to use the driver development tool Windriver,and completes the development of the PXI bus driver under the Visual 2010 platform.In the paper,detailed techniques for microwave radar signal conditioning and acquisition systems were performed.Finally,based on the completion of hardware and software design,various modules of the system were fully simulated and tested.The test results show that each module of the system achieves corresponding functions.The signal conditioning and acquisition system based on PXI bus developed in this paper basically meets the predetermined requirements.