Research Of Digital Audio Feedback Suppressor

The acoustical feedback phenomenon is quite common in the amplifying system. Howling, which results from the feedback, restricted the sound-amplification system’s gain from increasing and caused the sound to distort. when the feedback becomes serious, the system even can not go work normally. we adopts the traditional acoustic feedback suppression method is to improve the sound filed space, or cascade equalizers of frequency-shifters in the sound amplifying link, etc. Although the traditional method can reduce the acoustical feedback on certain level the occurrence, but they are not easy to operate, hurt the normal sound badly and only improve the system gain a little.With the years the rapid development of digital signal processing, a new generation of automatic acoustic feedback suppressor developed as DSP core. The automatic acoustical feedback suppressor and the traditional suppressor compared with easy operation, real-time property, little harm to speech, the system of sound transmission gain increasing etc. But most of the acoustic feedback suppressers available are imported from oversea, and they are expensive.Based on the above background, the paper introduces the LMS adaptive filtering algorithm, through to the algorithm research, and contrasts the plans which several kinds of the suppress acoustic feedback, by the result of the MATLAB simulation can be used to verify the rationality and the accuracy of the algorithm. The simulation experiment result simultaneously showed the algorithm play a good effect in speech signal noise cancellation system.Using the DSP chip TMS320F2812 as the core, the paper designed hardware of acoustic feedback suppression system based on TMS320F2812 according to the system requires in performance of price ratio. It put on the hardware composition and functional requirements of the system, including MCU module, McBSP module, etc, and the paper had programmed used algorithm. The whole system took the module circuit as foundation to start the design, and it has been validated by experiments and simulation. The experiment indicated that this method has displayed the adaptive filter algorithm characteristic and has very good inhibitory effect. It has realized the reasonable resources disposition.