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示例程序当中有一个AudioCallBack的程序， 当中有这样一段程序【1】。 我右击打开irdf1_fr32函数看到第二段#pragma开头的程序，那么子程序当中是通过IIRfilter处理音频的呢？
==============================================================================================【1】
/* Compute filter response */
void AudioFilter(const fract32 dataIn[], fract32 dataOut[])
{
int n;
int i;
/* separate channels (2D DMA would be better) */
i = 0;
for (n=0; n
inLeft[n] = dataIn[i++];
inRight[n] = dataIn[i++];
}
/* left channel filter */
iirdf1_fr32 (inLeft, outLeft, SAMPLES_PER_CHAN, &stateLeft);
/* right channel filter */
iirdf1_fr32 (inRight, outRight, SAMPLES_PER_CHAN, &stateRight);
/* combine channels (2D DMA would be better) */
i = 0;
for (n=0; n
dataOut[i++] = outLeft[n];
dataOut[i++] = outRight[n];
}
}
=========================================【2】
#pragma linkage_name __iirdf1_fr32
void iirdf1_fr32 (const fract32 _input[],
fract32 _output[], int _length,
iirdf1_state_fr32 *_filter_state);
源代码链接：
http://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/eval-bf706-mini.html
EmmaChenHenryL
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