The Research And Design On Automatic Acoustic Feedback Suppressor Based On DSP

Acoustic feedback is a common phenomenon in everyday life. In a variety of sound reinforcement system, acoustic feedback is a widespread phenomenon with the simultaneous use of the speaker and microphone. When the sound system volume to a larger increase, the speaker is often accompanied by howling appear. Howling produced here caused by acoustic feedback. The emergence of acoustic feedback limits the increase of system gain, and can not reach the PA effect. A direct result of acoustic feedback is sound distorted. When the distortion is more serious, it will cause howling. Howling not only put speech and performing not smoothly, but also the intense howling may burn the amplifier or speaker system, or even damage the human ear. Therefore, how to effectively suppress acoustic feedback and prevent acoustic feedback in sound reinforcement system is an important issue.Against this background, we designed an automatic acoustic feedback suppression system. The system is generally used in conference rooms, multimedia classrooms, hall and other common situations.This subject proposed an automatic acoustic feedback suppression algorithm, based on the causes and characteristics of the acoustic feedback. Automatic acoustic feedback suppression algorithm consists of two algorithms:digital equalization algorithm and automatic acoustic feedback suppression algorithm. For digital equalization algorithm, using the parametric equalizer design method. For automatic acoustic feedback suppression algorithm is divided into the detection of acoustic feedback and determine the part, the acoustic feedback suppression part. The detection and determination of acoustic feedback using Chirp-Z transform (CZT) algorithm combined with the FFT algorithm. The same time, designed a way to use nine IIR notch filter consisting of narrow-band filter for suppression of acoustic feedback.The subject introduces the design of hardware and software based on TMS320C5509 DSP, also the connections between system peripheral devices and DSP and Initial configuration of each module and algorithm implementation process on the system is introduced. At last the improved speech enhancement algorithm is successful operated on the hardware system. The system can play an inhibitory effect on the acoustic feedback, the basic purpose of rapid inhibition of the Howling and a small injury on the sound quality is achieved.