Researches Of Vibration Signal Acquisition And Analysis Using Sound Card

The acquisition and analysis of vibration signals are the bases for the application of vibration theory. The dynamic characteristics of a structure can be obtained by the analysis of its vibration signals. TheΣ?Δtype ADC and DAC are the key devices in the most of today's signal acquisition and generation systems. On the other hand, almost every personal computer (PC) has a sound card which works based onΣ?Δtype ADC and DAC. So, to make a sound card in a PC becoming a vibration signal meter and or a generator is very valuable in the practice.The contributions of the thesis are as following:1. The theory and the analysis methods of signal process are summarized and the properties of the measuring techniques of frequency transfer functions based on three kinds of excitation are put forward.2. A deep analysis is implemented to the hardware configuration of the sound card and the property of the audio frequency of Windows system. The setting to the software and hardware are founded in order to use the sound card as a vibration signal acquirer.3. The needing performance of the anti-aliasing filter for theΣ?Δtype ADC is derived based on the signal analysis theory. A kind of design method for anti-aliasing filter is presented.4. A software package with the functions of vibration signal acquisition, generation, monitoring, and record is finished based on LabVIEW. The difficulties of signal triggering, system calibration, the best sampling frequency selecting, acquisition points setting, magnitude modifying in low frequency range are all solved. The software package can be installed and used in any PC which is running on the Windows operating system.5. Verifying tests are performed on a beam structure for the developed vibration signal acquisition and generation system based on sound card and the results are compared with those of Agilent 35670A. The tests show that the developed system is useful.In summary, the developed vibration signal acquisition and generation system based on sound card in the thesis can be used as oscillograph, arbitrary signal generator, signal monitor and vibration and sound signal recorder at the occasions when the accuracy is not the main concerned problem. The use of the almost cost-free system can cut down a large amount of money invested on the expensive professional signal analyzer.