SampleSpectrum::SampleSpectrum(complex* time_signal,
double samp_intvl,
int num_samps)
: PsdEstimate(num_samps, samp_intvl)
{
complex* sample_spectrum = new complex[num_samps];
fft(time_signal, sample_spectrum, num_samps);
for (int samp_idx = 0; samp_idx < num_samps; samp_idx++) {
Psd_Est[samp_idx] = mag_sqrd(sample_spectrum[samp_idx]);
}
return;
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
int
LevinsonRecursion(complex* toeplitz, int ar_order, complex* avec,
double* ar_drv_var_ret)
{
complex sum, work, temp;
double ar_drv_var;
int j, k, kdiv2, kminj;
ar_drv_var = real(toeplitz[0]);
avec[0] = 1.0;
for (k = 1; k <= ar_order; k++)
avec[k] = 0.0;
for (k = 1; k <= ar_order; k++) {
sum = toeplitz[k];
for (j = 1; j < k; j++) {
sum += avec[j] * toeplitz[k - j];
}
work = -sum / ar_drv_var;
ar_drv_var *= (1.0 - mag_sqrd(work));
/*
if(ar_drv_var <= 0.0)
{
*ar_drv_var_ret = ar_drv_var;
return(1);
} */
avec[k] = work;
kdiv2 = k / 2;
for (j = 1; j <= kdiv2; j++) {
kminj = k - j;
temp = avec[j];
avec[j] = temp + work * conj(avec[kminj]);
if (j == kminj)
continue;
avec[kminj] += work * conj(temp);
}
#ifdef _DEBUG
DebugFile << "k = " << k << " ar_drv_var = " << ar_drv_var << std::endl;
#endif
} // end of loop over k
*ar_drv_var_ret = ar_drv_var;
return (0);
};
WelchPeriodogram::WelchPeriodogram(
SignalSource* signal_source,
double samp_intvl,
int num_samps_per_seg,
int shift_between_segs,
int fft_len,
GenericWindow* data_wind,
int num_segs_to_avg )
:PsdEstimate( num_samps_per_seg,
samp_intvl )
{
int samp_idx, seg_idx, ovrlap_len;
complex *time_seg, *ovrlap_seg, *new_seg, *freq_seg;
complex *windowed_seg;
double *win_seq;
double scale_factor;
std::cout << "in WelchPeriodogram" << std::endl;
Psd_Est = new double[fft_len];
time_seg = new complex[num_samps_per_seg];
windowed_seg = new complex[num_samps_per_seg];
freq_seg = new complex[fft_len];
if( (time_seg ==NULL)||
(windowed_seg ==NULL)||
(freq_seg ==NULL) )
{
std::cout << "Allocation error in freq_seg in WelchPeriodogram"
<< std::endl;
exit(99);
}
for(samp_idx=0; samp_idx < fft_len; samp_idx++)
{
Psd_Est[samp_idx] = 0.0;
}
if(data_wind != NULL)
win_seq = data_wind->GetDataWindow();
ovrlap_seg = time_seg + shift_between_segs;
ovrlap_len = num_samps_per_seg-shift_between_segs;
new_seg = time_seg + ovrlap_len;
// prefill overlap segment of buffer
signal_source->GetNextSegment(ovrlap_seg, ovrlap_len);
for(seg_idx = 0; seg_idx < num_segs_to_avg; seg_idx++)
{
// copy overlap samples down to start of buffer
memmove( time_seg, ovrlap_seg,
(sizeof(complex)/sizeof(char))*ovrlap_len);
// get new samples
signal_source->GetNextSegment(new_seg, shift_between_segs);
// apply window sequence to segment of time signal
if( data_wind == NULL)
{
for(samp_idx=0; samp_idx < num_samps_per_seg; samp_idx++)
{
windowed_seg[samp_idx] = time_seg[samp_idx];
}
}
else
{
for(samp_idx=0; samp_idx < num_samps_per_seg; samp_idx++)
{
windowed_seg[samp_idx] = win_seq[samp_idx] * time_seg[samp_idx];
}
}
//-----------------------------------
// compute FFT of windowed segment
fft(windowed_seg, freq_seg, num_samps_per_seg, fft_len);
for(samp_idx=0; samp_idx < fft_len; samp_idx++)
{
Psd_Est[samp_idx] += mag_sqrd(freq_seg[samp_idx]);
}
}
scale_factor = (float)num_segs_to_avg*num_samps_per_seg/samp_intvl;
for(samp_idx=0; samp_idx < fft_len; samp_idx++)
{
Psd_Est[samp_idx] /= scale_factor;
}
delete[] time_seg;
delete[] freq_seg;
delete[] windowed_seg;
return;
}
