void lpf_peak_pick(float *foff, float *max, COMP pilot_baseband[],
COMP pilot_lpf[], fft_cfg fft_pilot_cfg, COMP S[], int nin)
{
int i,j,k;
int mpilot;
COMP s[MPILOTFFT];
float mag, imax;
int ix;
float r;
/* LPF cutoff 200Hz, so we can handle max +/- 200 Hz freq offset */
for(i=0; i<NPILOTLPF-nin; i++)
pilot_lpf[i] = pilot_lpf[nin+i];
for(i=NPILOTLPF-nin, j=0; i<NPILOTLPF; i++,j++) {
pilot_lpf[i].real = 0.0; pilot_lpf[i].imag = 0.0;
for(k=0; k<NPILOTCOEFF; k++)
pilot_lpf[i] = cadd(pilot_lpf[i], fcmult(pilot_coeff[k], pilot_baseband[j+k]));
}
/* decimate to improve DFT resolution, window and DFT */
mpilot = FS/(2*200); /* calc decimation rate given new sample rate is twice LPF freq */
init_comp_array(s, MPILOTFFT);
for(i=0,j=0; i<NPILOTLPF; i+=mpilot,j++) {
s[j] = fcmult(hanning[i], pilot_lpf[i]);
}
fft_do(fft_pilot_cfg, s, S);
/* peak pick and convert to Hz */
imax = 0.0;
ix = 0;
for(i=0; i<MPILOTFFT; i++) {
mag = S[i].real*S[i].real + S[i].imag*S[i].imag;
if (mag > imax) {
imax = mag;
ix = i;
}
}
r = 2.0*200.0/MPILOTFFT; /* maps FFT bin to frequency in Hz */
if (ix >= MPILOTFFT/2)
*foff = (ix - MPILOTFFT)*r;
else
*foff = (ix)*r;
*max = imax;
}
void CODEC2_WIN32SUPPORT fdmdv_get_rx_spectrum(struct FDMDV *f, float mag_spec_dB[],
COMP rx_fdm[], int nin)
{
int i,j;
COMP fft_in[2*FDMDV_NSPEC];
COMP fft_out[2*FDMDV_NSPEC];
float full_scale_dB;
/* update buffer of input samples */
for(i=0; i<2*FDMDV_NSPEC-nin; i++)
f->fft_buf[i] = f->fft_buf[i+nin];
for(j=0; j<nin; j++,i++)
f->fft_buf[i] = rx_fdm[j].real;
assert(i == 2*FDMDV_NSPEC);
/* window and FFT */
for(i=0; i<2*FDMDV_NSPEC; i++) {
fft_in[i].real = f->fft_buf[i] * (0.5 - 0.5*cosf((float)i*2.0*PI/(2*FDMDV_NSPEC)));
fft_in[i].imag = 0.0;
}
fft_do(f->fft_cfg, fft_in, fft_out);
/* FFT scales up a signal of level 1 FDMDV_NSPEC */
full_scale_dB = 20*log10f(FDMDV_NSPEC);
/* scale and convert to dB */
for(i=0; i<FDMDV_NSPEC; i++) {
mag_spec_dB[i] = 10.0*log10f(fft_out[i].real*fft_out[i].real + fft_out[i].imag*fft_out[i].imag);
mag_spec_dB[i] -= full_scale_dB;
}
}
void draw_fft(void)
{
double mx_mag = 0.0;
int index = 0, highest = 0;
int cx = 0, cy = 0;
/* double max_freq = hz / 2.0; */
double highest_freq = 0, avg_freq_index = 0.0, total_val = 0.0, avg_freq = 0.0;
int dummy = 0;
getyx(w_slow, cy, cx);
for(index=0; index<max_x; index++)
{
double val = 0.0;
if (history_set[index])
val = history[index];
else
val = index > 0 ? history[index - 1] : 0;
if (val > graph_limit)
val = graph_limit;
history_temp[index] = val;
}
fft_do(history_temp, history_fft_magn, history_fft_phase);
for(index=1; index<max_x/2; index++)
{
avg_freq_index += (double)index * history_fft_magn[index];
total_val += history_fft_magn[index];
if (history_fft_magn[index] > mx_mag)
{
mx_mag = history_fft_magn[index];
highest = index;
}
}
highest_freq = (hz / (double)max_x) * (double)highest;
avg_freq_index /= total_val;
avg_freq = (hz / (double)max_x) * avg_freq_index;
wattron(w_line1, A_REVERSE);
myprintloc(w_line1, 0, 38, gettext("highest: %6.2fHz, avg: %6.2fHz"), highest_freq, avg_freq);
wattroff(w_line1, A_REVERSE);
wnoutrefresh(w_line1);
dummy = max_x / 2 + 1;
if (draw_phase)
{
int y = 0;
for(y=0; y<slow_n; y++)
mvwchgat(w_slow, y, dummy, 1, A_REVERSE, C_WHITE, NULL);
for(index=0; index<slow_n; index++)
mvwchgat(w_slow, index, 0, max_x, A_NORMAL, C_WHITE, NULL);
for(index=1; index<dummy - 1; index++)
draw_rad_column(w_slow, index - 1, history_fft_phase[index]);
}
else
{
for(index=0; index<slow_n; index++)
mvwchgat(w_slow, index, max_x / 2, max_x / 2, A_NORMAL, C_WHITE, NULL);
}
for(index=1; index<dummy; index++)
{
int height_magn = (int)((double)slow_n * (history_fft_magn[index] / mx_mag));
draw_column(w_slow, max_x / 2 + index - 1, height_magn, 0, 0);
}
wmove(w_slow, cy, cx);
wnoutrefresh(w_slow);
}
