// Process samples.
void PhaseDiscriminator::process(const IQSampleVector& samples_in,
SampleVector& samples_out)
{
unsigned int n = samples_in.size();
IQSample s0 = m_last1_sample;
samples_out.resize(n);
for (unsigned int i = 0; i < n; i++) {
IQSample s1(samples_in[i]);
IQSample d(conj(s0) * s1);
//Sample w = atan2(d.imag(), d.real());
Sample w = fastatan2(d.imag(), d.real()); // fast approximation of atan2
samples_out[i] = w * m_freq_scale_factor;
s0 = s1;
}
m_last2_sample = m_last1_sample;
m_last1_sample = s0;
}
static FP_TYPE* synth_noise(llsm_parameters param, llsm_conf conf, FP_TYPE** wrapped_spectrogram, int winsize) {
/*
To suppress glitches caused by aliasing, we apply MLT sine window twice, before analysis and after synthesis respectively;
Overlapping factor should be greater or equal to 4 for MLT sine window;
To preserve time resolution, we actually lower the hopsize by half, meanwhile double sampling wrapped_spectrogram.
*/
conf.nhop /= 2;
int nfft = winsize * conf.nhop * 2;
int ny = conf.nfrm * conf.nhop * 2 + nfft * 16;
FP_TYPE* y = calloc(ny, sizeof(FP_TYPE));
FP_TYPE* w = hanning(nfft);
FP_TYPE* realbuff = calloc(nfft, sizeof(FP_TYPE));
FP_TYPE* imagbuff = calloc(nfft, sizeof(FP_TYPE));
FP_TYPE* yfrm = calloc(nfft, sizeof(FP_TYPE));
FP_TYPE fftbuff[65536];
FP_TYPE norm_factor = 0.5 * sumfp(w, nfft);
FP_TYPE norm_factor_win = 0;
{
int i = 0;
while(i < nfft) {
norm_factor_win += w[i];
i += conf.nhop;
}
}
for(int j = 0; j < nfft; j ++)
w[j] = sqrt(w[j]);
FP_TYPE* x = white_noise(1.0, ny);
FP_TYPE* freqwrap = llsm_wrap_freq(0, conf.nosf, conf.nnos, conf.noswrap);
for(int i = 0; i < conf.nfrm * 2; i ++) {
int t = i * conf.nhop;
FP_TYPE* spec = llsm_spectrum_from_envelope(freqwrap, wrapped_spectrogram[i / 2], conf.nnos, nfft / 2, param.s_fs);
FP_TYPE* xfrm = fetch_frame(x, ny, t, nfft);
for(int j = 0; j < nfft; j ++)
xfrm[j] *= w[j];
fft(xfrm, NULL, realbuff, imagbuff, nfft, fftbuff);
for(int j = 0; j < nfft / 2; j ++) {
FP_TYPE a = fastexp(spec[j]) * norm_factor; // amplitude
FP_TYPE p = fastatan2(imagbuff[j], realbuff[j]);
realbuff[j] = a * cos(p);
imagbuff[j] = a * sin(p);
}
complete_symm (realbuff, nfft);
complete_asymm(imagbuff, nfft);
ifft(realbuff, imagbuff, yfrm, NULL, nfft, fftbuff);
for(int j = 0; j < nfft; j ++) {
int idx = t + j - nfft / 2;
if(idx >= 0)
y[idx] += yfrm[j] * w[j] / norm_factor_win;
}
free(spec);
free(xfrm);
}
free(w);
free(x);
free(yfrm);
free(realbuff);
free(imagbuff);
free(freqwrap);
return y;
}
