void ModemFMStereo::disposeKit(ModemKit *kit) {
ModemKitFMStereo *fmkit = (ModemKitFMStereo *)kit;
msresamp_rrrf_destroy(fmkit->audioResampler);
msresamp_rrrf_destroy(fmkit->stereoResampler);
firfilt_rrrf_destroy(fmkit->firStereoLeft);
firfilt_rrrf_destroy(fmkit->firStereoRight);
firhilbf_destroy(fmkit->firStereoR2C);
firhilbf_destroy(fmkit->firStereoC2R);
nco_crcf_destroy(fmkit->stereoPilot);
}
//
// AUTOTEST : fir group delay, n=3
//
void autotest_fir_groupdelay_n3()
{
// create coefficients array
float h[3] = {0.1, 0.2, 0.4};
float tol = 1e-3f;
unsigned int i;
// create testing vectors
float fc[4] = { 0.000,
0.125,
0.250,
0.375};
float g0[4] = { 1.42857142857143,
1.54756605839643,
2.15384615384615,
2.56861651421767};
// run tests
float g;
for (i=0; i<4; i++) {
g = fir_group_delay(h, 3, fc[i]);
CONTEND_DELTA( g, g0[i], tol );
}
// create filter
firfilt_rrrf filter = firfilt_rrrf_create(h,3);
// run tests again
for (i=0; i<4; i++) {
g = firfilt_rrrf_groupdelay(filter, fc[i]);
CONTEND_DELTA( g, g0[i], tol );
}
// destroy filter
firfilt_rrrf_destroy(filter);
}
void gmskdem_destroy(gmskdem _q)
{
#if DEBUG_GMSKDEM
// print to external file
gmskdem_debug_print(_q, DEBUG_GMSKDEM_FILENAME);
// destroy debugging objects
windowf_destroy(_q->debug_mfout);
#endif
// destroy filter object
#if GMSKDEM_USE_EQUALIZER
eqlms_rrrf_destroy(_q->eq);
#else
firfilt_rrrf_destroy(_q->filter);
#endif
// free filter array
free(_q->h);
// free main object memory
free(_q);
}
int main() {
// options
unsigned int h_len=17; // filter length
float fc=0.2f; // filter cutoff
float As=30.0f; // stop-band attenuation [dB]
float mu=0.0f; // timing offset
unsigned int n=64; // number of random input samples
// derived values
unsigned int num_samples = n + h_len;
// arrays
float x[num_samples]; // filter input
float y[num_samples]; // filter output
unsigned int i;
float h[h_len];
liquid_firdes_kaiser(h_len,fc,As,mu,h);
firfilt_rrrf f = firfilt_rrrf_create(h,h_len);
firfilt_rrrf_print(f);
for (i=0; i<num_samples; i++) {
// generate noise
x[i] = (i<n) ? randnf()/sqrtf(n/2) : 0.0f;
firfilt_rrrf_push(f, x[i]);
firfilt_rrrf_execute(f, &y[i]);
printf("x[%4u] = %12.8f, y[%4u] = %12.8f;\n", i, x[i], i, y[i]);
}
// destroy filter object
firfilt_rrrf_destroy(f);
//
// export results
//
FILE*fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% firfilt_rrrf_example.m: auto-generated file\n\n");
fprintf(fid,"clear all;\nclose all;\n\n");
fprintf(fid,"h_len=%u;\nn=%u;\n", h_len, n);
for (i=0; i<h_len; i++)
fprintf(fid,"h(%4u) = %12.4e;\n", i+1, h[i]);
for (i=0; i<num_samples; i++)
fprintf(fid,"x(%4u) = %12.4e; y(%4u) = %12.4e;\n", i+1, x[i], i+1, y[i]);
fprintf(fid,"nfft=512;\n");
fprintf(fid,"H=20*log10(abs(fftshift(fft(h,nfft))));\n");
fprintf(fid,"X=20*log10(abs(fftshift(fft(x,nfft))));\n");
fprintf(fid,"Y=20*log10(abs(fftshift(fft(y,nfft))));\n");
fprintf(fid,"f=[0:(nfft-1)]/nfft-0.5;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"plot(f,X,'Color',[0.3 0.3 0.3],...\n");
fprintf(fid," f,Y,'LineWidth',2,...\n");
fprintf(fid," f,H,'-b','LineWidth',2);\n");
fprintf(fid,"axis([-0.5 0.5 -80 40]);\n");
fprintf(fid,"grid on;\nxlabel('normalized frequency');\nylabel('PSD [dB]');\n");
fprintf(fid,"legend('noise','filtered noise','filter prototype',1);");
fclose(fid);
printf("results written to %s\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
int main(int argc, char*argv[])
{
// options
unsigned int h_len=19; // filter length
unsigned int p=5; // polynomial order
float fc=0.45f; // filter cutoff
float As=60.0f; // stop-band attenuation [dB]
float mu=0.1f; // fractional sample delay
unsigned int num_samples=60; // number of samples to evaluate
int verbose = 0; // verbose output?
int dopt;
while ((dopt = getopt(argc,argv,"hvt:")) != EOF) {
switch (dopt) {
case 'h': usage(); return 0;
case 'v': verbose = 1; break;
case 't': mu = atof(optarg); break;
default:
exit(1);
}
}
// data arrays
float x[num_samples]; // input data array
float y[num_samples]; // output data array
// create and initialize Farrow filter object
firfarrow_rrrf f = firfarrow_rrrf_create(h_len, p, fc, As);
firfarrow_rrrf_set_delay(f, mu);
unsigned int i;
// generate input (filtered noise)
float hx[21];
liquid_firdes_kaiser(15, 0.1, 60, 0, hx);
firfilt_rrrf fx = firfilt_rrrf_create(hx, 15);
for (i=0; i<num_samples; i++) {
firfilt_rrrf_push(fx, i < 40 ? randnf() : 0.0f);
firfilt_rrrf_execute(fx, &x[i]);
}
firfilt_rrrf_destroy(fx);
// push input through filter
for (i=0; i<num_samples; i++) {
firfarrow_rrrf_push(f, x[i]);
firfarrow_rrrf_execute(f, &y[i]);
}
// destroy Farrow filter object
firfarrow_rrrf_destroy(f);
FILE*fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s : auto-generated file\n\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\nclose all;\n\n");
fprintf(fid,"h_len = %u;\n", h_len);
fprintf(fid,"mu = %f;\n", mu);
fprintf(fid,"num_samples = %u;\n", num_samples);
for (i=0; i<num_samples; i++) {
fprintf(fid,"x(%4u) = %12.4e; y(%4u) = %12.4e;\n", i+1, x[i], i+1, y[i]);
}
// plot the results
fprintf(fid,"\n\n");
fprintf(fid,"figure;\n");
fprintf(fid,"tx = 0:(num_samples-1); %% input time scale\n");
fprintf(fid,"ty = tx - (h_len-1)/2 + mu; %% output time scale\n");
fprintf(fid,"plot(tx, x,'-s','MarkerSize',3, ...\n");
fprintf(fid," ty, y,'-s','MarkerSize',3);\n");
fprintf(fid,"legend('input','output',0);\n");
fclose(fid);
printf("results written to %s\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
int main() {
// spectral periodogram options
unsigned int nfft = 1024; // spectral periodogram FFT size
unsigned int num_samples = 4000; // number of samples
float beta = 10.0f; // Kaiser-Bessel window parameter
float noise_floor = -60.0f; // noise floor [dB]
float alpha = 0.1f; // PSD estimate bandwidth
unsigned int i;
// derived values
float nstd = powf(10.0f, noise_floor/20.0f);
// create spectral periodogram
unsigned int window_size = nfft/2; // spgramf window size
spgramf q = spgramf_create_kaiser(nfft, window_size, beta);
// generate signal (filter with frequency offset)
unsigned int h_len = 91; // filter length
float fc = 0.07f; // filter cut-off frequency
float f0 = 0.20f; // filter center frequency
float As = 60.0f; // filter stop-band attenuation
float h[h_len]; // filter coefficients
liquid_firdes_kaiser(h_len, fc, As, 0, h);
// add frequency offset
for (i=0; i<h_len; i++)
h[i] *= cosf(2*M_PI*f0*i);
firfilt_rrrf filter = firfilt_rrrf_create(h, h_len);
firfilt_rrrf_set_scale(filter, 2.0f*fc);
for (i=0; i<num_samples; i++) {
// generate random sample
float x = randnf();
// filter
float y = 0;
firfilt_rrrf_push(filter, x);
firfilt_rrrf_execute(filter, &y);
// add noise
y += nstd * randnf();
// push resulting sample through periodogram
spgramf_accumulate_psd(q, &y, alpha, 1);
}
// compute power spectral density output
float psd[nfft];
spgramf_write_accumulation(q, psd);
// destroy objects
firfilt_rrrf_destroy(filter);
spgramf_destroy(q);
//
// export output file
//
FILE * fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s : auto-generated file\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n\n");
fprintf(fid,"nfft = %u;\n", nfft);
fprintf(fid,"f = [0:(nfft-1)]/nfft - 0.5;\n");
fprintf(fid,"H = zeros(1,nfft);\n");
fprintf(fid,"noise_floor = %12.6f;\n", noise_floor);
for (i=0; i<nfft; i++)
fprintf(fid,"H(%6u) = %12.4e;\n", i+1, psd[i]);
fprintf(fid,"figure;\n");
fprintf(fid,"plot(f, H, '-', 'LineWidth',1.5);\n");
fprintf(fid,"xlabel('Normalized Frequency [f/F_s]');\n");
fprintf(fid,"ylabel('Power Spectral Density [dB]');\n");
fprintf(fid,"grid on;\n");
fprintf(fid,"ymin = 10*floor([noise_floor-20]/10);\n");
fprintf(fid,"ymax = 10*floor([noise_floor+80]/10);\n");
fprintf(fid,"axis([-0.5 0.5 ymin ymax]);\n");
fclose(fid);
printf("results written to %s.\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
