The Research Of Data Acquisition System For Acoustic Signal Based On Wireless Communication

In the dissertation, a wireless data acquisition system for acoustic signal is researched and realizes acoustic transmission with high quality voice and high precise delay. The system mainly applies to the acoustic localization in shooting range. It can make four channels of acquired acoustic signal produced by a projectile exploding transmit to the headquarters several kilometers away without distortion. Then their delays between each channel are calculated and the coordinate of exploding point is gained to help experimentalists find the warhead timely. Therefore, it can found the ballistic experimental data about projectile which is recorded by storage device when projectile was shooting.The whole system includes data acquisition and amplification of acoustic signal, anti-aliasing filtering circuit ,analog-to-digital converters(ADCs), synchronization NV SRAM and long-distance wireless digital communication system. Among them the anti-aliasing filtering circuit has the advantage of fine linear phase-frequency and high consistent group delay, which can avoid the defects of different delay at different frequencies in normal anti-aliasing filtering circuit, in favor of higher precision of coordinate calculation in subsequently signal processing. The problems of wave distortion brought by normal spring are properly solved through application of circulating SRAM and an acoustic signal are well recorded upon condition that the complexity of circuit is not increased. Long-distance wireless communication system mainly includes nRF905 chip and RF power amplifier chip MAX2235. Because of the PCB (Print Circuit Board) designed by using various RF EMC methods, the practical layout and circuit routing are greatly optimized. The communication system shows a high reliability in practical measuring and its communication distance can up to five kilometers with 1 watt of transmitting power, making the data acquired in field transmit to the headquarters reliably. About software, the realization of MCU control system is introduced emphatically,which includes the control of data acquisition and storage, operation of configuration words in wireless communication chip and the control of intercommunication between host and guest module. At the same time, the program flow-chats is given. Besides, the error bit rate in wireless communication system is proved very low by practical program testing.The system is the foundation of signal processing in computer, provides a reliable insurance for data acquisition in acoustic localizating in shooting range. The innovational point in dissertation includes the design of anti-aliasing filtering circuit and the application of circulating SRAM. The module of wirless communication successfully realized can also apply to production in industry ,daily life and military field etc., has a very well usage value and wide applicable space.