/// <summary>
/// 计算时域信号的复数频谱，包含幅度谱和相位谱信息
/// </summary>
/// <param name="waveform">时域波形数据</param>
/// <param name="windowType">窗类型</param>
/// <param name="spectrum">计算后的复数频谱数据</param>
public static void AdvanceComplexFFT(double[] waveform, WindowType windowType, ref Complex[] spectrum)
{
if (waveform == null || spectrum == null || spectrum.Length < (waveform.Length / 2 + 1))
{
throw new JYDSPUserBufferException();
}
int n = waveform.Length, windowsize = waveform.Length; //做FFT的次数
int fftsize = windowsize; //做FFT点数
double cg = 0, enbw = 0;
double[] xInTmp = null;
double[] windowData = null;
xInTmp = new double[fftsize];
GCHandle gchXIn = GCHandle.Alloc(waveform, GCHandleType.Pinned);
var xInPtr = gchXIn.AddrOfPinnedObject();
GCHandle gchXout = GCHandle.Alloc(spectrum, GCHandleType.Pinned);
var xOutPtr = gchXout.AddrOfPinnedObject();
try
{
//生成窗函数的数据
windowData = new double[windowsize];
Window.GetWindow(windowType, ref windowData, out cg, out enbw);
CBLASNative.cblas_dscal(windowsize, 1 / cg, windowData, 1); //窗系数归一化
CBLASNative.cblas_dscal(spectrum.Length, 0, xOutPtr, 1); //将xOut清零
/*TIME_DOMAIN_WINDOWS(windowType, x_in, &CG, &ENBW, windowsize);*//*(double*)(xIn + i * windowsize)*/
VMLNative.vdMul(windowsize, windowData, xInPtr, xInTmp);
BasicFFT.RealFFT(xInTmp, ref spectrum);
}
finally
{
gchXIn.Free();
gchXout.Free();
}
}
/// <summary>
/// 计算时域信号的复数频谱，包含幅度谱和相位谱信息
/// </summary>
/// <param name="waveform">时域波形数据</param>
/// <param name="spectralLines">频谱线的条数</param>
/// <param name="windowType">窗类型</param>
/// <param name="spectrum">计算后的复数频谱数据</param>
/// <param name="spectralInfo">返回的频谱数据的参数信息</param>
public static void AdvanceComplexFFT(double[] waveform, int spectralLines, WindowType windowType,
double[] spectrum, ref SpectralInfo spectralInfo)
{
int n = waveform.Length, windowsize = 0, fftcnt = 0; //做FFT的次数
int fftsize = 0; //做FFT点数
double cg = 0, enbw = 0, scale = 0.0;
double[] xInTmp = null;
double[] windowData = null;
Complex[] xOutCTmp = null;
//输入的线数超过最大支持的线数则使用最大支持线数
if (spectralLines > MaxSpectralLine)
{
spectralLines = MaxSpectralLine;
}
//输入的点数小于线数，则窗长度为N，先加窗再补零到2*spectralLines再做FFT
if (n <= 2 * spectralLines)
{
windowsize = n;
fftcnt = 1;
}
else
{
windowsize = 2 * spectralLines;
fftcnt = n / (2 * spectralLines);
}
fftsize = 2 * spectralLines; //不管N与2*spectralLines的关系是怎么样，FFT的点数都应该为 2*spectralLines
xInTmp = new double[fftsize];
xOutCTmp = new Complex[fftsize / 2 + 1];
if (n < (2 * spectralLines))
{
//memset(x_in + N, 0, (fftsize - N) * sizeof(double)); //补零至spectralLines
for (int i = n; i < fftsize; i++)
{
xInTmp[i] = 0;
}
}
//memset(xOut, 0, spectralLines * sizeof(double));
//生成窗函数的数据
windowData = new double[windowsize];
Window.GetWindow(windowType, ref windowData, out cg, out enbw);
CBLASNative.cblas_dscal(windowsize, 1 / cg, windowData, 1); //窗系数归一化
CBLASNative.cblas_dscal(spectrum.Length, 0, spectrum, 1); //将xOut清零
GCHandle gch = GCHandle.Alloc(waveform, GCHandleType.Pinned);
var xInPtr = gch.AddrOfPinnedObject();
for (int i = 0; i < fftcnt; i++)
{
//拷贝数据到临时内存中
//memcpy(x_in, x + i * windowsize, fftsize * sizeof(double));
/*TIME_DOMAIN_WINDOWS(windowType, x_in, &CG, &ENBW, windowsize);*//*(double*)(xIn + i * windowsize)*/
VMLNative.vdMul(windowsize, windowData, xInPtr + i * fftsize * sizeof(double), xInTmp);
BasicFFT.RealFFT(xInTmp, ref xOutCTmp);
//计算FFT结果复数的模,复用x_in做中间存储
VMLNative.vzAbs(fftsize / 2 + 1, xOutCTmp, xInTmp);
//每次计算结果累加起来
VMLNative.vdAdd(spectralLines, xInTmp, spectrum, spectrum);
}
scale = 2 * (1.0 / fftcnt) / Sqrt2; //双边到单边有一个二倍关系,输出为Vrms要除以根号2
//fftcnt次的频谱做平均
CBLASNative.cblas_dscal(spectralLines, scale, spectrum, 1);
spectrum[0] = spectrum[0] / Sqrt2; //上一步零频上多除了根号2，这里乘回来（Rms在零频上不用除根号2，单双边到单边还是要乘2 ?）
spectralInfo.spectralLines = spectralLines;
spectralInfo.FFTSize = fftsize;
spectralInfo.windowSize = windowsize;
spectralInfo.windowType = windowType;
gch.Free();
}
