Research Of The Test Technique For A Tube Of Low Frequency

Noise control is an important direction of acoustic research, according to different objects; it can be divided into active noise control and passive noise control. Sound absorption is an important part of passive acoustic noise control, so measurements of sound absorption materials is an important part of acoustic noise control.In this thesis, based on comprehensive analysis of basic errors of pulse-tube method, standing wave ratio method, transfer function method of the traditional sound control.Technology, the thesis focus on measuring principle of one-way reception method, the thesis numerically analyze and simulate the effects of measured channel mismatch, speed of sound in water, hydrophone spacing, hydrophone spacing, the samples and other factors on the measurement results of reflection coefficient. The thesis proposed online Calibration of measuring channel mismatch method and method of controlling medium speed of sound in water testing based on total reflection absolute soft interface, the thesis also completes the overall program design of low frequency sound system.By using of electronic equipment in the bus control hardware configuration and integration, the thesis developed a real-time measurement of low frequency sound control software based on the successful use of VB language. By trial, the system is stable and reliable. The development of the low-frequency acoustic tube measurement system based on one-way reception method provides an effective way of measuring low-frequency acoustic properties of acoustic materials Samples, which is helpful for the low-frequency sound absorption performance test of sound-absorbing material.