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对生活中常见的啸叫现象,设计了一个具备啸叫检测与抑制功能的实时音频功率放大系统。根据啸叫产生前期的频域特征,采用FFT对音频信号进行频域转换,并采用峰值平均功率比方法检测啸频点;采用基于可编程滤波器的硬件滤波电路完成啸叫的抑制;并设计了高效率数字音频功放电路、未音电路及输入滤波电路。实验表明该设计频点检测准确、啸叫抑制效果明显、音频无明显失真。相比杂的全数字算法搭配高性能处理器的抑制方式,具有成本低、设计难度低、硬件抑制电路响应更快等点,在多媒体教室、学术报告厅及会议室等实时扩音场合有较高的实用价值。
A common real-time howling phenomenon in life is designed with a real-time audio power amplification system with howling detection and suppression. According to the characteristics of early frequency response of howling, the frequency domain of the audio signal is converted by FFT and the peak-to-average power ratio is used to detect howling frequency. The hardware filter circuit based on programmable filter is used to suppress howling. A high-efficiency digital audio amplifier circuit, not the sound circuit and input filter circuit. Experiments show that the design frequency detection accuracy, whistle suppression effect is obvious, the audio without obvious distortion. Compared with miscellaneous all-digital algorithm with high-performance processor suppression, with low cost, low design difficulty, hardware suppression circuit response faster, such as multimedia classrooms, academic lectures and conference rooms and other real-time PA occasions High practical value.