音频系统中抗啸叫电路方案设计

The audio system of anti howling circuit design

话筒拾音的音频系统中,都有反馈啸叫的可能。通过对多种啸叫抑制方法的比较,提出一种新型抗啸叫电路设计方案。系统包括音频放大器的设计和抗啸叫电路方案的设计。音频放大器的设计利用基于TI的功率放大器芯片TPA3112D1,并通过MCU实现输出功率可控。抗啸叫电路的设计选用MAX264构成陷波滤波器,以切除啸叫频率点信号达到啸叫抑制的目的,其中MAX264时钟频率由函数发生器ICL8038按扫频信号电路连接产生。利用音频系统作为啸叫测试平台,其结果表明采用陷波法设计的电路方案能够有效地实现啸叫点的检测与抑制,设计方案简单、实用且处理后的音质无明显畸变,能应用于多种场合。

It is possible to howling in the audio system. Comparing the various howling suppression methods, we presents a new program of anti-howling circuit design. The system includes the design of audio amplifier and anti-howling circuit program. The design of audio amplifier choosing the chip of TPA3112D1, and achieve the goal that output power adjustable by MCU. In order to remove the howling frequency signal to achieve the purpose of the howling suppression, we select the chip of MAX264 to constitute notch filter, which the clock frequency produce from the function generator circuit ICL8038. Using the audio system as howling test platform, the results show that the circuit scheme used notch method can effectively achieve the howling detection and suppression.Its quality has no obvious distortion and the design program is simple and practical,which can be applied to a variety of occasions.