Exemple #1
0
vcd fft(const vcd& a, bool invert=false)
{
    int n = a.size();
    vcd A(a.size());
    for(int i=0, j=0; i<a.size(); ++i)
    {
        A[j] = a[i];
        int bit = n>>1;
        for(; j>=bit && bit>1; bit>>=1)
            j -= bit;
        j += bit;
    }
    for(int s=2; s<=n; s<<=1)
    {
        double ang = 2 * pi / s * (invert ? -1 : 1);
        cd ws(cos(ang), sin(ang));
        for(int j=0; j<n; j+=s)
        {
            cd w=1;
            for(int k=0; k<s/2; k++)
            {
                cd u = A[j+k];
                cd t = A[j+s/2+k];
                A[j+k] = u + w * t;
                A[j+s/2+k] = u - w * t;
                w *= ws;
            }
        }
    }
    if(invert)
        foreach(i,A)
            A[i] /= n;
    return A;
}
Exemple #2
0
 void fft_inv(vcd& a) {
   fft(a);
   for (int i = 0; i < N; ++i) {
     a[i] /= N;
   }
   //now we have the identity matrix from the bottom to top
   reverse(a.begin() + 1, a.end());
 }
Exemple #3
0
void fft(vcd &a, bool invert)
{
	int n = a.size();
	if (n == 1)
		return;

	vcd a0, a1;
	a0.resize(n / 2); a1.resize(n / 2);
	for (int i = 0, j = 0; i < n; i += 2, ++j)
	{
		a0[j] = a[i];
		a1[j] = a[i + 1];
	}
	fft(a0, invert);
	fft(a1, invert);

	double ang = 2 * 3.14159265359 / n * (invert ? -1 : 1);
	complex<double> w(1), wn(cos(ang), sin(ang));

	for (int i = 0; i < n / 2; ++i)
	{
		a[i] = a0[i] + (w * a1[i]);
		a[i + n / 2] = a0[i] - (w * a1[i]);
		w = w * wn;
	}
	if (invert)
	{
		for (int i = 0; i < n; ++i)
			a[i] /= 2;
	}
}
Exemple #4
0
double rms(vcd v)
{
	int num = v.size();
	double temp = 0.0;
	vd temp_v(num);
	
	for (int z=0; z<num; z++) {temp_v[z]=pow(abs(v[z]),2);} // t1=abs(v)^2
	temp = accumulate(&temp_v[0],&temp_v[num-1],temp_v[num-1])/(1.0*num); // t2=mean(t1)
	temp = sqrt(temp); // rms=sqrt(t2)

	return temp;
}
vcd fft(const vcd & v, bool inverse = false) {
  static const double PI = acos(-1.0);
  int n = v.size(), k = 0, high1 = -1;
  while ((1 << k) < n) k++;
  std::vector<int> rev(n);
  rev[0] = 0;
  for (int i = 1; i < n; i++) {
    if ((i & (i - 1)) == 0) high1++;
    rev[i] = rev[i ^ (1 << high1)];
    rev[i] |= (1 << (k - high1 - 1));
  }
  vcd roots(n), res(n);
  for (int i = 0; i < n; i++) {
    double alpha = 2 * PI * i / n;
    roots[i] = cd(cos(alpha), sin(alpha));
  }
  for (int i = 0; i < n; i++) res[i] = v[rev[i]];
  for (int len = 1; len < n; len <<= 1) {
    vcd tmp(n);
    int rstep = roots.size() / (len * 2);
    for (int pdest = 0; pdest < n;) {
      int p1 = pdest;
      for (int i = 0; i < len; i++) {
        cd val = roots[i * rstep] * res[p1 + len];
        tmp[pdest] = res[p1] + val;
        tmp[pdest + len] = res[p1] - val;
        pdest++, p1++;
      }
      pdest += len;
    }
    res.swap(tmp);
  }
  if (inverse) {
    for (int i = 0; i < (int)res.size(); i++) res[i] /= v.size();
    std::reverse(res.begin() + 1, res.end());
  }
  return res;
}
Exemple #6
0
  void init() {
    int hb = -1;
    rev.assign(N, 0);
    _root.assign(N, 0);

    for (int i = 1; i < N; ++i) {
      if ((i & (i - 1)) == 0) {
        ++hb;
      }
      rev[i] = rev[i ^ (1 << hb)];
      rev[i] |= (1 << (LOG - hb - 1));
    }
    for (int i = 0; i < N; ++i) {
      ld angle = 2.0 * PI * i / (1.0 * N);
      _root[i] = cd(cosl(angle), sinl(angle));
    }
  }
void FFT(vcd & IN,vcd & OUT,int n,bool perform_inv){ 
	bit_rev(IN,OUT,n);
	for(int s = 1,lg = len(n) - 1;s <= lg;s++){
		int m = (1 << s);
		cd wm = cd(cos(2.0*PI/m),sin(2.0*PI/m));
		for(int k = 0;k < n;k += m){
			cd w = cd(1.0,0.0);
			for(int j = 0;j < m/2;j++){
				cd t = w*OUT[k + j + m/2];
				cd u = OUT[k + j];
				OUT[k + j] = u + t;
				OUT[k + j + m/2] = u - t;
				if(perform_inv) w /= wm;
				else w *= wm;
			}
		}
	}
	if(perform_inv) for(int i = 0;i < OUT.size();i++) OUT[i] /= n;
}
Exemple #8
0
void display(vi E,vcd st,vi du,vi dc,vi sym,vcd s,vcd n,vcd r,vi sym_est,vi sym_err,vi destu,vi destc,vi berru,vi berrc)
{
	cout << endl;
	cout<<"       Symbol Table: "; for(int n=0;n<st.size();n++){cout<< st[n]<<" ";} cout<<endl;
	//cout<<"                RMS: " << RMS <<endl;
	//cout << endl;
	//cout<<"          Signal TX: "; for (int z=0;z<s.size();z++){cout<<s[z]<<" ";} cout<<endl;
	//cout<<"              Noise: "; for (int z=0;z<n.size();z++){cout<<n[z]<<" ";} cout<<endl;
	//cout<<"          Signal RX: "; for (int z=0;z<r.size();z++){cout<<r[z]<<" ";} cout<<endl;
	cout << endl;
	cout<<"       Sym. Ind. TX: "; for(int z=0;z<sym.size();z++){cout<<sym[z]<<" ";} cout<<endl;
	cout<<"     Sym. Ind. Est.: "; for(int z=0;z<sym_est.size();z++){cout<<sym_est[z]<<" ";} cout<<endl;
	cout<<"         Sym. Error: "; for(int z=0;z<sym_err.size();z++){cout<<sym_err[z]<<" ";} cout<<endl;
	cout << endl;
	cout<<"       Data (Coded): "; for(int z=0;z<dc.size();z++){cout<<dc[z];} cout<<endl;
	cout<<"  Data Est. (Coded): "; for(int z=0;z<destc.size();z++){cout<<destc[z];} cout<<endl;
	cout<<"  Bit Error (Coded): "; for(int z=0;z<berrc.size();z++){cout<<berrc[z];} cout<<endl;
	cout << endl;
	cout<<"     Data (Uncoded): "; for(int z=0;z<du.size();z++){cout<<du[z];} cout<<endl;
	cout<<"Data Est. (Uncoded): "; for(int z=0;z<destu.size();z++){cout<<destu[z];} cout<<endl;
	cout<<"Bit Error (Uncoded): "; for(int z=0;z<berru.size();z++){cout<<berru[z];} cout<<endl;
	cout << endl;
}