// create spgram object
// _nfft : FFT size
// _wtype : window type, e.g. LIQUID_WINDOW_HAMMING
// _window_len : window length
// _delay : delay between transforms, _delay > 0
SPGRAM() SPGRAM(_create)(unsigned int _nfft,
int _wtype,
unsigned int _window_len,
unsigned int _delay)
{
// validate input
if (_nfft < 2) {
fprintf(stderr,"error: spgram%s_create(), fft size must be at least 2\n", EXTENSION);
exit(1);
} else if (_window_len > _nfft) {
fprintf(stderr,"error: spgram%s_create(), window size cannot exceed fft size\n", EXTENSION);
exit(1);
} else if (_window_len == 0) {
fprintf(stderr,"error: spgram%s_create(), window size must be greater than zero\n", EXTENSION);
exit(1);
} else if (_wtype == LIQUID_WINDOW_KBD && _window_len % 2) {
fprintf(stderr,"error: spgram%s_create(), KBD window length must be even\n", EXTENSION);
exit(1);
} else if (_delay == 0) {
fprintf(stderr,"error: spgram%s_create(), delay must be greater than 0\n", EXTENSION);
exit(1);
}
// allocate memory for main object
SPGRAM() q = (SPGRAM()) malloc(sizeof(struct SPGRAM(_s)));
// set input parameters
q->nfft = _nfft;
q->wtype = _wtype;
q->window_len = _window_len;
q->delay = _delay;
q->frequency = 0;
q->sample_rate= -1;
// set object for full accumulation
SPGRAM(_set_alpha)(q, -1.0f);
// create FFT arrays, object
q->buf_time = (TC*) malloc((q->nfft)*sizeof(TC));
q->buf_freq = (TC*) malloc((q->nfft)*sizeof(TC));
q->psd = (T *) malloc((q->nfft)*sizeof(T ));
q->fft = FFT_CREATE_PLAN(q->nfft, q->buf_time, q->buf_freq, FFT_DIR_FORWARD, FFT_METHOD);
// create buffer
q->buffer = WINDOW(_create)(q->window_len);
// create window
q->w = (T*) malloc((q->window_len)*sizeof(T));
unsigned int i;
unsigned int n = q->window_len;
float beta = 10.0f;
float zeta = 3.0f;
for (i=0; i<n; i++) {
switch (q->wtype) {
case LIQUID_WINDOW_HAMMING: q->w[i] = hamming(i,n); break;
case LIQUID_WINDOW_HANN: q->w[i] = hann(i,n); break;
case LIQUID_WINDOW_BLACKMANHARRIS: q->w[i] = blackmanharris(i,n); break;
case LIQUID_WINDOW_BLACKMANHARRIS7: q->w[i] = blackmanharris7(i,n); break;
case LIQUID_WINDOW_KAISER: q->w[i] = kaiser(i,n,beta,0); break;
case LIQUID_WINDOW_FLATTOP: q->w[i] = flattop(i,n); break;
case LIQUID_WINDOW_TRIANGULAR: q->w[i] = triangular(i,n,n); break;
case LIQUID_WINDOW_RCOSTAPER: q->w[i] = liquid_rcostaper_windowf(i,n/3,n); break;
case LIQUID_WINDOW_KBD: q->w[i] = liquid_kbd(i,n,zeta); break;
default:
fprintf(stderr,"error: spgram%s_create(), invalid window\n", EXTENSION);
exit(1);
}
}
// scale by window magnitude, FFT size
float g = 0.0f;
for (i=0; i<q->window_len; i++)
g += q->w[i] * q->w[i];
g = M_SQRT2 / ( sqrtf(g / q->window_len) * sqrtf((float)(q->nfft)) );
// scale window and copy
for (i=0; i<q->window_len; i++)
q->w[i] = g * q->w[i];
// reset the spgram object
q->num_samples_total = 0;
q->num_transforms_total = 0;
SPGRAM(_reset)(q);
// return new object
return q;
}
int main() {
// options
unsigned int h_len = 7; // filter semi-length (filter delay)
float r=1/sqrtf(2); // resampling rate (output/input)
float bw=0.25f; // resampling filter bandwidth
float As=60.0f; // resampling filter stop-band attenuation [dB]
unsigned int npfb=32; // number of filters in bank (timing resolution)
unsigned int n=180; // number of input samples
// number of input samples (adjusted for filter delay)
unsigned int nx = n + h_len;
// generate input sequence : windowed sum of complex sinusoids
unsigned int i;
float complex x[nx];
for (i=0; i<nx; i++) {
float complex jphi = _Complex_I*2.0f*M_PI*i;
x[i] = cexpf(jphi*0.02f) + 1.4f*cexpf(jphi*0.07f);
// window edge size
unsigned int t = (unsigned int)(0.1*n);
if (i < n) {
// edge-rounded window
if (i < t) x[i] *= blackmanharris(i,2*t);
else if (i >= n-t) x[i] *= blackmanharris(n-i-1,2*t);
} else {
x[i] = 0.;
}
}
// output buffer with extra padding for good measure
unsigned int y_len = (unsigned int) ceilf(1.1*r*nx) + 16;
float complex y[y_len];
// create resampler
resamp_crcf f = resamp_crcf_create(r,h_len,bw,As,npfb);
unsigned int num_written;
unsigned int ny=0;
for (i=0; i<nx; i++) {
// execute resampler, storing in output buffer
resamp_crcf_execute(f, x[i], &y[ny], &num_written);
ny += num_written;
}
printf(" %u / %u\n", ny, nx);
// clean up allocated objects
resamp_crcf_destroy(f);
// open/initialize output file
FILE*fid = fopen(OUTPUT_FILENAME_TIME,"w");
fprintf(fid,"# %s: auto-generated file\n\n", OUTPUT_FILENAME_TIME);
fprintf(fid,"reset\n");
fprintf(fid,"set terminal postscript eps enhanced color solid rounded\n");
//fprintf(fid,"set xrange [0:%u];\n",n);
fprintf(fid,"set yrange [-3:3]\n");
fprintf(fid,"set size ratio 0.3\n");
fprintf(fid,"set xlabel 'Input Sample Index'\n");
fprintf(fid,"set key top right nobox\n");
fprintf(fid,"set ytics -5,1,5\n");
fprintf(fid,"set grid xtics ytics\n");
fprintf(fid,"set pointsize 0.6\n");
fprintf(fid,"set grid linetype 1 linecolor rgb '%s' lw 1\n", LIQUID_DOC_COLOR_GRID);
fprintf(fid,"set multiplot layout 2,1 scale 1.0,1.0\n");
fprintf(fid,"# real\n");
fprintf(fid,"set ylabel 'Real'\n");
fprintf(fid,"plot '-' using 1:2 with linespoints pointtype 7 linetype 1 linewidth 1 linecolor rgb '#999999' title 'original',\\\n");
fprintf(fid," '-' using 1:2 with points pointtype 7 linecolor rgb '#008000' title 'resampled'\n");
// export output
for (i=0; i<nx; i++) {
//fprintf(fid,"%6u %12.4e %12.4e\n", i, cos(2*M_PI*0.04*i), sin(2*M_PI*0.04*i));
fprintf(fid,"%6u %12.4e %12.4e\n", i, crealf(x[i]), cimagf(x[i]));
}
fprintf(fid,"e\n");
float t;
for (i=0; i<ny; i++) {
t = (float)(i) / r - (float)(h_len);
fprintf(fid,"%12.4e %12.4e %12.4e\n", t, crealf(y[i]), cimagf(y[i]));
}
fprintf(fid,"e\n");
fprintf(fid,"# imag\n");
fprintf(fid,"set ylabel 'Imag'\n");
fprintf(fid,"plot '-' using 1:3 with linespoints pointtype 7 linetype 1 linewidth 1 linecolor rgb '#999999' title 'original',\\\n");
fprintf(fid," '-' using 1:3 with points pointtype 7 linecolor rgb '#800000' title 'resampled'\n");
// export output
for (i=0; i<nx; i++) {
//fprintf(fid,"%6u %12.4e %12.4e\n", i, cos(2*M_PI*0.04*i), sin(2*M_PI*0.04*i));
fprintf(fid,"%6u %12.4e %12.4e\n", i, crealf(x[i]), cimagf(x[i]));
}
fprintf(fid,"e\n");
for (i=0; i<ny; i++) {
t = (float)(i) / r - (float)(h_len);
fprintf(fid,"%12.4e %12.4e %12.4e\n", t, crealf(y[i]), cimagf(y[i]));
}
fprintf(fid,"e\n");
fprintf(fid,"unset multiplot\n");
// close output file
fclose(fid);
fid = fopen(OUTPUT_FILENAME_FREQ,"w");
unsigned int nfft = 512;
float complex X[nfft];
float complex Y[nfft];
liquid_doc_compute_psdcf(x,nx,X,nfft,LIQUID_DOC_PSDWINDOW_HANN,0);
liquid_doc_compute_psdcf(y,ny,Y,nfft,LIQUID_DOC_PSDWINDOW_HANN,0);
fft_shift(X,nfft);
fft_shift(Y,nfft);
float scaling_factor = 20*log10f(nfft);
fprintf(fid,"# %s: auto-generated file\n\n", OUTPUT_FILENAME_FREQ);
fprintf(fid,"reset\n");
fprintf(fid,"set terminal postscript eps enhanced color solid rounded\n");
fprintf(fid,"set xrange [-0.5:0.5];\n");
fprintf(fid,"set yrange [-120:20]\n");
fprintf(fid,"set size ratio 0.6\n");
fprintf(fid,"set xlabel 'Normalized Input Frequency'\n");
fprintf(fid,"set ylabel 'Power Spectral Density [dB]'\n");
fprintf(fid,"set key top right nobox\n");
fprintf(fid,"set grid xtics ytics\n");
fprintf(fid,"set pointsize 0.6\n");
fprintf(fid,"set grid linetype 1 linecolor rgb '%s' lw 1\n",LIQUID_DOC_COLOR_GRID);
fprintf(fid,"# real\n");
fprintf(fid,"plot '-' using 1:2 with lines linetype 1 linewidth 4 linecolor rgb '#999999' title 'original',\\\n");
fprintf(fid," '-' using 1:2 with lines linetype 1 linewidth 4 linecolor rgb '#004080' title 'resampled'\n");
// export output
for (i=0; i<nfft; i++) {
float fx = (float)(i) / (float)nfft - 0.5f;
fprintf(fid,"%12.8f %12.4e\n", fx, 20*log10f(cabsf(X[i])) - scaling_factor);
}
fprintf(fid,"e\n");
for (i=0; i<nfft; i++) {
float fy = ((float)(i) / (float)nfft - 0.5f)*r;
fprintf(fid,"%12.8f %12.4e\n", fy, 20*log10f(cabsf(Y[i])) - scaling_factor - 20*log10(r));
}
fprintf(fid,"e\n");
fclose(fid);
printf("done.\n");
return 0;
}