Signal Conditioning Circuit Design Based On PXI Bus

Within the gun projectile motion parameters measured in the process of the project research found that through AD sampling card to doppler microwave radar signals sometimes could not reach the requirements of software processing the signal. Aiming at the problem in the project, the need for signal conditioning, to improve the quality of the signal, facilitate subsequent signal research. This paper analyzes the interior ballistic characteristic of doppler signal, microwave radar based on PXI bus is designed for signal conditioning circuit to deal with the problem encountered in the project, to study the interior ballistic projectile parameter measurement has important engineering application value.Of signal through the signal processing software found after data processing, the target is always added in a low frequency vibration signal, if the low frequency signal is too big, in the wave will be cut to useful signal, thus affecting the analysis of the target signal. This paper designed the circuit will be low frequency signal and noise filtering, and with the function of automatic gain control, signal amplitude of the automatic control, to achieve the purpose of improve the quality of the signal. Board core part, automatic gain control circuit detection circuit in the determination of the time constant of this is related to the board can be a key part of the normal work, through a series of calculation and simulation and practical signal, and ultimately determine the size of the time constant. Paper mainly introduced the adaptive signal control unit and PXI bus data transfer module technical index analysis and parameter calculation.For adaptive signal control unit, mainly in the circuit design, simulation, schematic design and PCB board production, design the adaptive filter control module, in the design of automatic gain control detection circuit mainly solved the key problems such as the size of the time constant, and the circuit board performance whether meet the requirements under the laboratory environment for debugging and analysis; In view of the PXI bus interface problems, has carried out the design of hardware circuit and software driver debugging, design of the PXI bus driver, with adaptive signal disposal and the key to solve the of the PXI bus interface matching is designed, and the PXI bus data transmission experiments have been carried out to verify whether can normal work.The experimental results show that the interface card used for actual projects, found that the signal has improved to some extent, achieve the actual effect.