public void ForwardFft(WWComplex[] aFrom, WWComplex[] aTo)
{
if (aFrom == null || aFrom.Length != mNumPoints
|| aTo == null || aTo.Length != mNumPoints) {
throw new ArgumentException();
}
WWComplex [] aTmp0 = new WWComplex[mNumPoints];
for (int i=0; i < aTmp0.Length; ++i) {
aTmp0[i] = new WWComplex(aFrom[mBitReversalTable[i]]);
}
WWComplex [] aTmp1 = new WWComplex[mNumPoints];
for (int i=0; i<aTmp1.Length; ++i) {
aTmp1[i] = new WWComplex();
}
WWComplex [][] aTmps = new WWComplex[2][];
aTmps[0] = aTmp0;
aTmps[1] = aTmp1;
for (int i=0; i<mNumStage-1; ++i) {
FftStageN(i, aTmps[((i&1) == 1) ? 1 : 0], aTmps[((i&1) == 0) ? 1 : 0]);
}
FftStageN(mNumStage - 1, aTmps[(((mNumStage - 1) & 1) == 1) ? 1 : 0], aTo);
}
public WWRadix2Fft(int numPoints)
{
if (!IsPowerOfTwo(numPoints) || numPoints < 2) {
throw new ArgumentException();
}
mNumPoints = numPoints;
mWn = new WWComplex[mNumPoints];
for (int i=0; i < mNumPoints; ++i) {
double angle = -2.0 * Math.PI * i / mNumPoints;
mWn[i] = new WWComplex(Math.Cos(angle), Math.Sin(angle));
}
// mNumStage == log_2(mNumPoints)
int t = mNumPoints;
for (int i=0; 0 < t; ++i) {
t >>= 1;
mNumStage = i;
}
mBitReversalTable = new uint[mNumPoints];
for (uint i=0; i < mNumPoints; ++i) {
mBitReversalTable[i] = BitReversal(mNumStage, i);
}
}
public WWComplex Mul(WWComplex rhs)
{
#if false
// straightforward but slow
double tR = real * rhs.real - imaginary * rhs.imaginary;
double tI = real * rhs.imaginary + imaginary * rhs.real;
real = tR;
imaginary = tI;
#else
// more efficient way
double k1 = real * (rhs.real + rhs.imaginary);
double k2 = rhs.imaginary * (real + imaginary);
double k3 = rhs.real * (imaginary - real);
real = k1 - k2;
imaginary = k1 + k3;
#endif
return this;
}
public void InverseFft(WWComplex[] aFrom, WWComplex[] aTo, double? compensation = null)
{
for (int i=0; i < aFrom.LongLength; ++i) {
aFrom[i].imaginary *= -1.0;
}
ForwardFft(aFrom, aTo);
double c = 1.0 / mNumPoints;
if (compensation != null) {
c = (double)compensation;
}
for (int i=0; i < aTo.LongLength; ++i) {
aTo[i].real *= c;
aTo[i].imaginary *= -1.0 * c;
}
}
private void UpdateMagnitudePhase()
{
var timeDomain = new WWComplex[SampleCount()];
for (int i=0; i < timeDomain.Length; ++i) {
timeDomain[i] = new WWComplex(mSLArray[i].Value, 0);
}
var freqDomain = new WWComplex[SampleCount()];
for (int i=0; i < freqDomain.Length; ++i) {
freqDomain[i] = new WWComplex();
}
var fft = new WWRadix2Fft(SampleCount());
fft.ForwardFft(timeDomain, freqDomain);
UpdateMagnitude(freqDomain);
UpdatePhase(freqDomain);
}
private void UpdateMagnitude(WWComplex [] freqDomain)
{
double pointIntervalX = (canvasWaveFormFR.ActualWidth - GRAPH_YAXIS_POS_X) / (SampleCount() / 2 + 1);
LineSetX1Y1X2Y2(lineFRX,
GRAPH_YAXIS_POS_X, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X,
canvasWaveFormFR.ActualWidth, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X);
LineSetX1Y1X2Y2(lineFRY,
GRAPH_YAXIS_POS_X, 0,
GRAPH_YAXIS_POS_X, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X);
LineSetX1Y1X2Y2(lineFRTickPHalf,
GRAPH_YAXIS_POS_X - 4, (canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X) / 2,
GRAPH_YAXIS_POS_X, (canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X) / 2);
LineSetX1Y1X2Y2(lineFRTickPMax,
GRAPH_YAXIS_POS_X - 4, 0,
GRAPH_YAXIS_POS_X, 0);
LineSetX1Y1X2Y2(lineFRTickXPi,
canvasWaveFormFR.ActualWidth - pointIntervalX, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X - 4,
canvasWaveFormFR.ActualWidth - pointIntervalX, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X);
CanvasSetLeftTop(labelFRPMax, 0, -labelFRPMax.ActualHeight / 2);
CanvasSetLeftTop(labelFRPHalf, 0, (canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X) / 2 - labelFRPHalf.ActualHeight/2);
CanvasSetLeftTop(labelFR0, 0, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X-labelFR0.ActualHeight/2);
CanvasSetLeftTop(labelFRXPi,
canvasWaveFormFR.ActualWidth - pointIntervalX - labelFRXPi.ActualWidth / 2, canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X);
labelFRPMax.Content = string.Format("{0}", SampleCount());
labelFRPHalf.Content = string.Format("{0}", SampleCount()/2);
foreach (var t in mMagnitudeGraph.points) {
canvasWaveFormFR.Children.Remove(t.Item1);
canvasWaveFormFR.Children.Remove(t.Item2);
}
mMagnitudeGraph.points.Clear();
for (int i=0; i < SampleCount()/2+1; ++i) {
double x = GRAPH_YAXIS_POS_X + pointIntervalX * i;
double y = canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X - (canvasWaveFormFR.ActualHeight - GRAPH_YAXIS_POS_X) * freqDomain[i].Magnitude() / SampleCount();
var el = new Ellipse();
el.Width = 6;
el.Height = 6;
el.Fill = Brushes.Black;
canvasWaveFormFR.Children.Add(el);
CanvasSetLeftTop(el, x - 3, y - 3);
var la = new Label();
la.Content = string.Format("{0:0.00}", freqDomain[i].Magnitude());
canvasWaveFormFR.Children.Add(la);
CanvasSetLeftTop(la, x, y-labelFRPMax.ActualHeight/2);
mMagnitudeGraph.points.Add(new Tuple<Ellipse, Label>(el, la));
}
}
public void CopyFrom(WWComplex rhs)
{
real = rhs.real;
imaginary = rhs.imaginary;
}
public WWComplex Add(WWComplex rhs)
{
real += rhs.real;
imaginary += rhs.imaginary;
return this;
}
public WWComplex(WWComplex rhs)
{
this.real = rhs.real;
this.imaginary = rhs.imaginary;
}
private void FftStageN(int stageNr, WWComplex[] x, WWComplex[] y)
{
/*
* stage0: 2つの入力データにバタフライ演算 (n=8の時) 4回 (nRepeat=4, nSubRepeat=2)
* y[0] = x[0] + w_n^(0*4) * x[1]
* y[1] = x[0] + w_n^(1*4) * x[1]
*
* y[2] = x[2] + w_n^(0*4) * x[3]
* y[3] = x[2] + w_n^(1*4) * x[3]
*
* y[4] = x[4] + w_n^(0*4) * x[5]
* y[5] = x[4] + w_n^(1*4) * x[5]
*
* y[6] = x[6] + w_n^(0*4) * x[7]
* y[7] = x[6] + w_n^(1*4) * x[7]
*/
/*
* stage1: 4つの入力データにバタフライ演算 (n=8の時) 2回 (nRepeat=2, nSubRepeat=4)
* y[0] = x[0] + w_n^(0*2) * x[2]
* y[1] = x[1] + w_n^(1*2) * x[3]
* y[2] = x[0] + w_n^(2*2) * x[2]
* y[3] = x[1] + w_n^(3*2) * x[3]
*
* y[4] = x[4] + w_n^(0*2) * x[6]
* y[5] = x[5] + w_n^(1*2) * x[7]
* y[6] = x[4] + w_n^(2*2) * x[6]
* y[7] = x[5] + w_n^(3*2) * x[7]
*/
/*
* stage2: 8つの入力データにバタフライ演算 (n=8の時) 1回 (nRepeat=1, nSubRepeat=8)
* y[0] = x[0] + w_n^(0*1) * x[4]
* y[1] = x[1] + w_n^(1*1) * x[5]
* y[2] = x[2] + w_n^(2*1) * x[6]
* y[3] = x[3] + w_n^(3*1) * x[7]
* y[4] = x[0] + w_n^(4*1) * x[4]
* y[5] = x[1] + w_n^(5*1) * x[5]
* y[6] = x[2] + w_n^(6*1) * x[6]
* y[7] = x[3] + w_n^(7*1) * x[7]
*/
/*
* stageN:
*/
int nRepeat = Pow2(mNumStage - stageNr - 1);
int nSubRepeat = mNumPoints / nRepeat;
var t = new WWComplex();
for (int i=0; i<nRepeat; ++i) {
int offsBase = i * nSubRepeat;
bool allZero = true;
for (int j=0; j < nSubRepeat/2; ++j) {
int offs = offsBase + (j % (nSubRepeat/2));
if (Double.Epsilon < x[offs].Magnitude()) {
allZero = false;
break;
}
if (Double.Epsilon < x[offs + nSubRepeat / 2].Magnitude()) {
allZero = false;
break;
}
}
if (allZero) {
for (int j=0; j < nSubRepeat / 2; ++j) {
y[j + offsBase].Set(0, 0);
}
} else {
for (int j=0; j < nSubRepeat; ++j) {
int offs = offsBase + (j % (nSubRepeat / 2));
y[j + offsBase].CopyFrom(x[offs]);
t.CopyFrom(mWn[j * nRepeat]);
t.Mul(x[offs + nSubRepeat / 2]);
y[j + offsBase].Add(t);
}
}
}
}
public void CopyFrom(WWComplex rhs)
{
real = rhs.real;
imaginary = rhs.imaginary;
}
public WWComplex Add(WWComplex rhs)
{
real += rhs.real;
imaginary += rhs.imaginary;
return(this);
}
public WWComplex(WWComplex rhs)
{
this.real = rhs.real;
this.imaginary = rhs.imaginary;
}
private void FftStageN(int stageNr, WWComplex[] x, WWComplex[] y)
{
/*
* stage0: 2つの入力データにバタフライ演算 (n=8の時) 4回 (nRepeat=4, nSubRepeat=2)
* y[0] = x[0] + w_n^(0*4) * x[1]
* y[1] = x[0] + w_n^(1*4) * x[1]
*
* y[2] = x[2] + w_n^(0*4) * x[3]
* y[3] = x[2] + w_n^(1*4) * x[3]
*
* y[4] = x[4] + w_n^(0*4) * x[5]
* y[5] = x[4] + w_n^(1*4) * x[5]
*
* y[6] = x[6] + w_n^(0*4) * x[7]
* y[7] = x[6] + w_n^(1*4) * x[7]
*/
/*
* stage1: 4つの入力データにバタフライ演算 (n=8の時) 2回 (nRepeat=2, nSubRepeat=4)
* y[0] = x[0] + w_n^(0*2) * x[2]
* y[1] = x[1] + w_n^(1*2) * x[3]
* y[2] = x[0] + w_n^(2*2) * x[2]
* y[3] = x[1] + w_n^(3*2) * x[3]
*
* y[4] = x[4] + w_n^(0*2) * x[6]
* y[5] = x[5] + w_n^(1*2) * x[7]
* y[6] = x[4] + w_n^(2*2) * x[6]
* y[7] = x[5] + w_n^(3*2) * x[7]
*/
/*
* stage2: 8つの入力データにバタフライ演算 (n=8の時) 1回 (nRepeat=1, nSubRepeat=8)
* y[0] = x[0] + w_n^(0*1) * x[4]
* y[1] = x[1] + w_n^(1*1) * x[5]
* y[2] = x[2] + w_n^(2*1) * x[6]
* y[3] = x[3] + w_n^(3*1) * x[7]
* y[4] = x[0] + w_n^(4*1) * x[4]
* y[5] = x[1] + w_n^(5*1) * x[5]
* y[6] = x[2] + w_n^(6*1) * x[6]
* y[7] = x[3] + w_n^(7*1) * x[7]
*/
/*
* stageN:
*/
int nRepeat = Pow2(mNumStage - stageNr - 1);
int nSubRepeat = mNumPoints / nRepeat;
var t = new WWComplex();
for (int i = 0; i < nRepeat; ++i)
{
int offsBase = i * nSubRepeat;
bool allZero = true;
for (int j = 0; j < nSubRepeat / 2; ++j)
{
int offs = offsBase + (j % (nSubRepeat / 2));
if (Double.Epsilon < x[offs].Magnitude())
{
allZero = false;
break;
}
if (Double.Epsilon < x[offs + nSubRepeat / 2].Magnitude())
{
allZero = false;
break;
}
}
if (allZero)
{
for (int j = 0; j < nSubRepeat / 2; ++j)
{
y[j + offsBase].Set(0, 0);
}
}
else
{
for (int j = 0; j < nSubRepeat; ++j)
{
int offs = offsBase + (j % (nSubRepeat / 2));
y[j + offsBase].CopyFrom(x[offs]);
t.CopyFrom(mWn[j * nRepeat]);
t.Mul(x[offs + nSubRepeat / 2]);
y[j + offsBase].Add(t);
}
}
}
}
private void UpdatePhase(WWComplex[] freqDomain)
{
double pointIntervalX = (canvasWaveFormPhase.ActualWidth - GRAPH_YAXIS_POS_X) / (SampleCount() / 2 + 1);
LineSetX1Y1X2Y2(linePX,
GRAPH_YAXIS_POS_X, canvasWaveFormPhase.ActualHeight / 2,
canvasWaveFormPhase.ActualWidth, canvasWaveFormPhase.ActualHeight / 2);
LineSetX1Y1X2Y2(linePY,
GRAPH_YAXIS_POS_X, 0,
GRAPH_YAXIS_POS_X, canvasWaveFormPhase.ActualHeight);
LineSetX1Y1X2Y2(linePTickPPi,
GRAPH_YAXIS_POS_X - 4, 0,
GRAPH_YAXIS_POS_X, 0);
LineSetX1Y1X2Y2(linePTickMPi,
GRAPH_YAXIS_POS_X - 4, canvasWaveFormPhase.ActualHeight-1,
GRAPH_YAXIS_POS_X, canvasWaveFormPhase.ActualHeight-1);
LineSetX1Y1X2Y2(linePTickXPi,
canvasWaveFormPhase.ActualWidth - pointIntervalX, canvasWaveFormPhase.ActualHeight / 2 - 4,
canvasWaveFormPhase.ActualWidth - pointIntervalX, canvasWaveFormPhase.ActualHeight / 2);
CanvasSetLeftTop(labelPPPi, 0, 0 - labelPPPi.ActualHeight / 2);
CanvasSetLeftTop(labelPMPi, 0, canvasWaveFormPhase.ActualHeight - labelPMPi.ActualHeight/2);
CanvasSetLeftTop(labelP0, 0, canvasWaveFormPhase.ActualHeight / 2 - labelPMPi.ActualHeight / 2);
CanvasSetLeftTop(labelPXPi,
canvasWaveFormPhase.ActualWidth - pointIntervalX - labelPXPi.ActualWidth/2, canvasWaveFormPhase.ActualHeight / 2);
foreach (var t in mPhaseGraph.points) {
canvasWaveFormPhase.Children.Remove(t.Item1);
canvasWaveFormPhase.Children.Remove(t.Item2);
}
mPhaseGraph.points.Clear();
for (int i=0; i < SampleCount() / 2 + 1; ++i) {
double x = GRAPH_YAXIS_POS_X + pointIntervalX * i;
double y = canvasWaveFormPhase.ActualHeight/2 - (canvasWaveFormPhase.ActualHeight)/2/Math.PI * freqDomain[i].Phase();
var el = new Ellipse();
el.Width = 6;
el.Height = 6;
el.Fill = Brushes.Black;
canvasWaveFormPhase.Children.Add(el);
CanvasSetLeftTop(el, x - 3, y - 3);
var la = new Label();
la.Content = string.Format("{0:0.00}", freqDomain[i].Phase());
canvasWaveFormPhase.Children.Add(la);
CanvasSetLeftTop(la, x, y - labelP0.ActualHeight/2);
mPhaseGraph.points.Add(new Tuple<Ellipse, Label>(el, la));
}
}
private void UpdateUpsampleGraph()
{
LineSetX1Y1X2Y2(lineUSX,
0, canvasUpsampleGraph.ActualHeight / 2,
canvasUpsampleGraph.ActualWidth, canvasUpsampleGraph.ActualHeight / 2);
LineSetX1Y1X2Y2(lineUSY,
GRAPH_YAXIS_POS_X, 0,
GRAPH_YAXIS_POS_X, canvasUpsampleGraph.ActualHeight);
LineSetX1Y1X2Y2(lineUSTickP1,
GRAPH_YAXIS_POS_X - 4, canvasUpsampleGraph.ActualHeight / 4,
GRAPH_YAXIS_POS_X, canvasUpsampleGraph.ActualHeight / 4);
LineSetX1Y1X2Y2(lineUSTickM1,
GRAPH_YAXIS_POS_X - 4, canvasUpsampleGraph.ActualHeight * 3 / 4,
GRAPH_YAXIS_POS_X, canvasUpsampleGraph.ActualHeight * 3 / 4);
CanvasSetLeftTop(labelUSP1, 0, canvasUpsampleGraph.ActualHeight / 4 - labelUSP1.ActualHeight / 2);
CanvasSetLeftTop(labelUS0, 0, canvasUpsampleGraph.ActualHeight / 2 - labelUS0.ActualHeight / 2);
CanvasSetLeftTop(labelUSM1, 0, canvasUpsampleGraph.ActualHeight * 3 / 4 - labelUSM1.ActualHeight / 2);
foreach (var t in mUpsampleGraph.points)
{
canvasUpsampleGraph.Children.Remove(t.Item1);
canvasUpsampleGraph.Children.Remove(t.Item2);
canvasUpsampleGraph.Children.Remove(t.Item3);
}
mUpsampleGraph.points.Clear();
// オリジナルPCMデータtimeDomainOrigをFFTして周波数ドメインデータfreqDomainOrigを得る
var timeDomainOrig = new WWComplex[SampleCount()];
for (int i = 0; i < timeDomainOrig.Length; ++i)
{
timeDomainOrig[i] = new WWComplex(mSLArray[i].Value, 0);
}
var freqDomainOrig = new WWComplex[SampleCount()];
{
var fft = new WWRadix2Fft(SampleCount());
fft.ForwardFft(timeDomainOrig, freqDomainOrig);
}
timeDomainOrig = null;
// 周波数ドメインデータfreqDomainOrigを0で水増ししたデータfreqDomainUpsampledを作って逆FFTする
int upsampledSampleCount = SampleCount() * UpsampleMultiple();
var freqDomainUpsampled = new WWComplex[upsampledSampleCount];
for (int i = 0; i < freqDomainUpsampled.Length; ++i)
{
if (i <= freqDomainOrig.Length / 2)
{
freqDomainUpsampled[i].CopyFrom(freqDomainOrig[i]);
if (i == freqDomainOrig.Length / 2)
{
freqDomainUpsampled[i].Mul(0.5);
}
}
else if (freqDomainUpsampled.Length - freqDomainOrig.Length / 2 <= i)
{
int pos = i + freqDomainOrig.Length - freqDomainUpsampled.Length;
freqDomainUpsampled[i].CopyFrom(freqDomainOrig[pos]);
if (freqDomainUpsampled.Length - freqDomainOrig.Length / 2 == i)
{
freqDomainUpsampled[i].Mul(0.5);
}
}
else
{
// do nothing
}
}
freqDomainOrig = null;
var timeDomainUpsampled = new WWComplex[upsampledSampleCount];
{
var fft = new WWRadix2Fft(upsampledSampleCount);
fft.InverseFft(freqDomainUpsampled, timeDomainUpsampled, 1.0 / SampleCount());
}
freqDomainUpsampled = null;
// アップサンプルされたPCMデータtimeDomainUpsampledをグラフにプロットする
double pointIntervalX = (canvasUpsampleGraph.ActualWidth - GRAPH_YAXIS_POS_X) / (upsampledSampleCount + 2 * UpsampleMultiple());
for (int i = 0; i < upsampledSampleCount; ++i)
{
double x = GRAPH_YAXIS_POS_X + pointIntervalX * (i + UpsampleMultiple());
double y = canvasUpsampleGraph.ActualHeight / 2 - (canvasUpsampleGraph.ActualHeight / 4) * timeDomainUpsampled[i].real;
var el = new Ellipse();
el.Width = 6;
el.Height = 6;
el.Fill = Brushes.Black;
canvasUpsampleGraph.Children.Add(el);
CanvasSetLeftTop(el, x - 3, y - 3);
var la = new Label();
la.Content = string.Format("{0:0.00}", timeDomainUpsampled[i].real);
canvasUpsampleGraph.Children.Add(la);
if (timeDomainUpsampled[i].real >= 0)
{
CanvasSetLeftTop(la, x - 16, y - labelUS0.ActualHeight);
}
else
{
CanvasSetLeftTop(la, x - 16, y);
}
var li = new Line();
li.Stroke = Brushes.Black;
canvasUpsampleGraph.Children.Add(li);
LineSetX1Y1X2Y2(li,
x, y,
x, canvasUpsampleGraph.ActualHeight / 2);
mUpsampleGraph.points.Add(new Tuple <Ellipse, Label, Line>(el, la, li));
}
}
private void UpdateUpsampleGraph()
{
LineSetX1Y1X2Y2(lineUSX,
0, canvasUpsampleGraph.ActualHeight / 2,
canvasUpsampleGraph.ActualWidth, canvasUpsampleGraph.ActualHeight / 2);
LineSetX1Y1X2Y2(lineUSY,
GRAPH_YAXIS_POS_X, 0,
GRAPH_YAXIS_POS_X, canvasUpsampleGraph.ActualHeight);
LineSetX1Y1X2Y2(lineUSTickP1,
GRAPH_YAXIS_POS_X - 4, canvasUpsampleGraph.ActualHeight / 4,
GRAPH_YAXIS_POS_X, canvasUpsampleGraph.ActualHeight / 4);
LineSetX1Y1X2Y2(lineUSTickM1,
GRAPH_YAXIS_POS_X - 4, canvasUpsampleGraph.ActualHeight * 3 / 4,
GRAPH_YAXIS_POS_X, canvasUpsampleGraph.ActualHeight * 3 / 4);
CanvasSetLeftTop(labelUSP1, 0, canvasUpsampleGraph.ActualHeight / 4 - labelUSP1.ActualHeight / 2);
CanvasSetLeftTop(labelUS0, 0, canvasUpsampleGraph.ActualHeight / 2 - labelUS0.ActualHeight / 2);
CanvasSetLeftTop(labelUSM1, 0, canvasUpsampleGraph.ActualHeight * 3 / 4 - labelUSM1.ActualHeight / 2);
foreach (var t in mUpsampleGraph.points) {
canvasUpsampleGraph.Children.Remove(t.Item1);
canvasUpsampleGraph.Children.Remove(t.Item2);
canvasUpsampleGraph.Children.Remove(t.Item3);
}
mUpsampleGraph.points.Clear();
// オリジナルPCMデータtimeDomainOrigをFFTして周波数ドメインデータfreqDomainOrigを得る
var timeDomainOrig = new WWComplex[SampleCount()];
for (int i=0; i < timeDomainOrig.Length; ++i) {
timeDomainOrig[i] = new WWComplex(mSLArray[i].Value, 0);
}
var freqDomainOrig = new WWComplex[SampleCount()];
{
var fft = new WWRadix2Fft(SampleCount());
fft.ForwardFft(timeDomainOrig, freqDomainOrig);
}
timeDomainOrig = null;
// 周波数ドメインデータfreqDomainOrigを0で水増ししたデータfreqDomainUpsampledを作って逆FFTする
int upsampledSampleCount = SampleCount() * UpsampleMultiple();
var freqDomainUpsampled = new WWComplex[upsampledSampleCount];
for (int i=0; i < freqDomainUpsampled.Length; ++i) {
if (i <= freqDomainOrig.Length / 2) {
freqDomainUpsampled[i].CopyFrom(freqDomainOrig[i]);
if (i == freqDomainOrig.Length / 2) {
freqDomainUpsampled[i].Mul(0.5);
}
} else if (freqDomainUpsampled.Length - freqDomainOrig.Length / 2 <= i) {
int pos = i + freqDomainOrig.Length - freqDomainUpsampled.Length;
freqDomainUpsampled[i].CopyFrom(freqDomainOrig[pos]);
if (freqDomainUpsampled.Length - freqDomainOrig.Length / 2 == i) {
freqDomainUpsampled[i].Mul(0.5);
}
} else {
// do nothing
}
}
freqDomainOrig = null;
var timeDomainUpsampled = new WWComplex[upsampledSampleCount];
{
var fft = new WWRadix2Fft(upsampledSampleCount);
fft.InverseFft(freqDomainUpsampled, timeDomainUpsampled, 1.0 / SampleCount());
}
freqDomainUpsampled = null;
// アップサンプルされたPCMデータtimeDomainUpsampledをグラフにプロットする
double pointIntervalX = (canvasUpsampleGraph.ActualWidth - GRAPH_YAXIS_POS_X) / (upsampledSampleCount + 2 * UpsampleMultiple());
for (int i=0; i < upsampledSampleCount; ++i) {
double x = GRAPH_YAXIS_POS_X + pointIntervalX * (i + UpsampleMultiple());
double y = canvasUpsampleGraph.ActualHeight / 2 - (canvasUpsampleGraph.ActualHeight / 4) * timeDomainUpsampled[i].real;
var el = new Ellipse();
el.Width = 6;
el.Height = 6;
el.Fill = Brushes.Black;
canvasUpsampleGraph.Children.Add(el);
CanvasSetLeftTop(el, x - 3, y - 3);
var la = new Label();
la.Content = string.Format("{0:0.00}", timeDomainUpsampled[i].real);
canvasUpsampleGraph.Children.Add(la);
if (timeDomainUpsampled[i].real >= 0) {
CanvasSetLeftTop(la, x - 16, y - labelUS0.ActualHeight);
} else {
CanvasSetLeftTop(la, x - 16, y);
}
var li = new Line();
li.Stroke = Brushes.Black;
canvasUpsampleGraph.Children.Add(li);
LineSetX1Y1X2Y2(li,
x, y,
x, canvasUpsampleGraph.ActualHeight / 2);
mUpsampleGraph.points.Add(new Tuple<Ellipse, Label, Line>(el, la, li));
}
}
private void Butterfly(WWComplex vFrom0, WWComplex vFrom1, WWComplex wn, WWComplex[] vTo, int toPos)
{
vTo[toPos].CopyFrom(vFrom0);
WWComplex t = new WWComplex(vFrom1);
t.Mul(wn);
vTo[toPos].Mul(t);
vTo[toPos + 1].CopyFrom(vFrom0);
t.Mul(-1);
vTo[toPos + 1].Mul(t);
}
