基于原型法的数字参量均衡器设计

在音频处理中，均衡器可以改变音频信号的频响特性，它是由多个峰值滤波器组成的，并且它要求每个滤波器的通带可在0dB上下变化，以实现系统的滤波特性，如通过在整个频段中的某几个频段进行提升或削减一定的分贝数，以达到满意的听觉效果，由于参量均衡器对滤波器的频响要求及参数调节方法有其特殊性，因此它的设计方法也有其自身的特点，采用双二阶函数作为滤波器的原型函数，通过简单的双线性变换，得到数字参量均衡器的各个系数，在实际应用中这些系数可以在事先计算好，需要时将它们加载到DSP中去。

Design of digital parametric equalizer based on function prototype

In audio signal processing, equalizer can adjust the response characteristic of amplitude to frequency of audio signal, equalizer consists of multiple bandpass filters. The passband of each filter of equalizers can be varied about the 0 dB level ,thereby realizing a filter system capable of boosting or cutting an input signal at the prescribed decibel within multiple frequency bands, therefore, a good effect will be produced. The design of parametric equalizer has its peculiarity because of its particular amplitude to frequency feature and its parameters adjustment way. Analyzing the characteristics of biquadratic function, a biquadratic function acted as peak\|filter prototype, we apply a bilinear transformation to it, and then get all coefficients of digital parametric equalizers. In practical application, these coefficients can be calculated in advance, and can be download to DSP in demand.filter of equalizers can be varied abou