/// <summary>
/// Calculates IIR.
/// </summary>
/// <param name="sample">sample rate</param>
/// <param name="pBiquad">BiquadCoefficients pointer</param>
public void BiQuad(ref byte sample, BiquadCoefficients* pBiquad)
{
// compute result
double result = pBiquad->a0 * sample + pBiquad->a1 * pBiquad->x1 +
pBiquad->a2 * pBiquad->x2 - pBiquad->a3 * pBiquad->y1 - pBiquad->a4 * pBiquad->y2;
// shift x1 to x2, sample to x1
pBiquad->x2 = pBiquad->x1;
pBiquad->x1 = sample;
// shift y1 to y2, result to y1
pBiquad->y2 = pBiquad->y1;
pBiquad->y1 = result;
sample = (byte)result;
}
private static extern bool HeapFree(IntPtr hHeap, uint dwFlags, BiquadCoefficients* lpMem);
/// <summary>Release heap memory</summary>
/// <param name="pmem">memory address</param>
private void Free(BiquadCoefficients* b)
{
HeapFree(GetProcessHeap(), 0, b);
}
/// <summary>
///
/// </summary>
/// <param name="b"></param>
public void FreeMem(BiquadCoefficients* b)
{
Free(b);
}
