// Helper function to keep code base small
void firpfbch2_crcf_execute_bench(struct rusage * _start,
struct rusage * _finish,
unsigned long int * _num_iterations,
unsigned int _num_channels,
unsigned int _m,
int _type)
{
// initialize channelizer
float As = 60.0f;
firpfbch2_crcf q = firpfbch2_crcf_create_kaiser(_type,_num_channels,_m,As);
unsigned long int i;
float complex x[_num_channels];
float complex y[_num_channels];
for (i=0; i<_num_channels; i++)
x[i] = 1.0f + _Complex_I*1.0f;
// scale number of iterations to keep execution time
// relatively linear
*_num_iterations /= _num_channels;
// start trials
getrusage(RUSAGE_SELF, _start);
for (i=0; i<(*_num_iterations); i++) {
firpfbch2_crcf_execute(q, x, y);
firpfbch2_crcf_execute(q, x, y);
firpfbch2_crcf_execute(q, x, y);
firpfbch2_crcf_execute(q, x, y);
}
getrusage(RUSAGE_SELF, _finish);
*_num_iterations *= 4;
firpfbch2_crcf_destroy(q);
}
int main(int argc, char*argv[])
{
// options
unsigned int num_channels=16; // number of channels
unsigned int m = 5; // filter semi-length (symbols)
unsigned int num_symbols=25; // number of symbols
float As = 80.0f; // filter stop-band attenuation
int dopt;
while ((dopt = getopt(argc,argv,"hM:m:s:n:")) != EOF) {
switch (dopt) {
case 'h': usage(); return 0;
case 'M': num_channels = atoi(optarg); break;
case 'm': m = atoi(optarg); break;
case 's': As = atof(optarg); break;
case 'n': num_symbols = atof(optarg); break;
default:
exit(1);
}
}
unsigned int i;
// validate input
if (num_channels < 2 || num_channels % 2) {
fprintf(stderr,"error: %s, number of channels must be greater than 2 and even\n", argv[0]);
exit(1);
} else if (m == 0) {
fprintf(stderr,"error: %s, filter semi-length must be greater than zero\n", argv[0]);
exit(1);
} else if (num_symbols == 0) {
fprintf(stderr,"error: %s, number of symbols must be greater than zero", argv[0]);
exit(1);
}
// derived values
unsigned int num_samples = num_channels * num_symbols;
// allocate arrays
float complex x[num_samples];
float complex y[num_samples];
// generate input signal
unsigned int w_len = (unsigned int)(0.4*num_samples);
for (i=0; i<num_samples; i++) {
//x[i] = (i==0) ? 1.0f : 0.0f;
//x[i] = cexpf( (-0.05f + 0.07f*_Complex_I)*i ); // decaying complex exponential
x[i] = cexpf( _Complex_I * (1.3f*i - 0.007f*i*i) );
x[i] *= i < w_len ? hamming(i,w_len) : 0.0f;
//x[i] = (i==0) ? 1.0f : 0.0f;
}
// create filterbank objects from prototype
firpfbch2_crcf qa = firpfbch2_crcf_create_kaiser(LIQUID_ANALYZER, num_channels, m, As);
firpfbch2_crcf qs = firpfbch2_crcf_create_kaiser(LIQUID_SYNTHESIZER, num_channels, m, As);
firpfbch2_crcf_print(qa);
firpfbch2_crcf_print(qs);
// run channelizer
float complex Y[num_channels];
for (i=0; i<num_samples; i+=num_channels/2) {
// run analysis filterbank
firpfbch2_crcf_execute(qa, &x[i], Y);
// run synthesis filterbank
firpfbch2_crcf_execute(qs, Y, &y[i]);
}
// destroy fiterbank objects
firpfbch2_crcf_destroy(qa); // analysis fitlerbank
firpfbch2_crcf_destroy(qs); // synthesis filterbank
// print output
for (i=0; i<num_samples; i++)
printf("%4u : %12.8f + %12.8fj\n", i, crealf(y[i]), cimagf(y[i]));
// compute RMSE
float rmse = 0.0f;
unsigned int delay = 2*num_channels*m - num_channels/2 + 1;
for (i=0; i<num_samples; i++) {
float complex err = y[i] - (i < delay ? 0.0f : x[i-delay]);
rmse += crealf( err*conjf(err) );
}
rmse = sqrtf( rmse/(float)num_samples );
printf("rmse : %12.4e\n", rmse);
//
// EXPORT DATA TO FILES
//
FILE * fid = NULL;
fid = fopen(OUTPUT_FILENAME_TIME,"w");
fprintf(fid,"# %s: auto-generated file\n", OUTPUT_FILENAME_TIME);
fprintf(fid,"#\n");
fprintf(fid,"# %8s %12s %12s %12s %12s %12s %12s\n",
"time", "real(x)", "imag(x)", "real(y)", "imag(y)", "real(e)", "imag(e)");
// save input and output arrays
for (i=0; i<num_samples; i++) {
float complex e = (i < delay) ? 0.0f : y[i] - x[i-delay];
fprintf(fid," %8.1f %12.4e %12.4e %12.4e %12.4e %12.4e %12.4e\n",
(float)i,
crealf(x[i]), cimagf(x[i]),
crealf(y[i]), cimagf(y[i]),
crealf(e), cimagf(e));
}
fclose(fid);
printf("results written to '%s'\n", OUTPUT_FILENAME_TIME);
//
// export frequency data
//
unsigned int nfft = 2048;
float complex y_time[nfft];
float complex y_freq[nfft];
for (i=0; i<nfft; i++)
y_time[i] = i < num_samples ? y[i] : 0.0f;
fft_run(nfft, y_time, y_freq, LIQUID_FFT_FORWARD, 0);
// filter spectrum
unsigned int h_len = 2*num_channels*m+1;
float h[h_len];
float fc = 0.5f/(float)num_channels;
liquid_firdes_kaiser(h_len, fc, As, 0.0f, h);
float complex h_time[nfft];
float complex h_freq[nfft];
for (i=0; i<nfft; i++)
h_time[i] = i < h_len ? 2*h[i]*fc : 0.0f;
fft_run(nfft, h_time, h_freq, LIQUID_FFT_FORWARD, 0);
// error spectrum
float complex e_time[nfft];
float complex e_freq[nfft];
for (i=0; i<nfft; i++)
e_time[i] = i < delay || i > num_samples ? 0.0f : y[i] - x[i-delay];
fft_run(nfft, e_time, e_freq, LIQUID_FFT_FORWARD, 0);
fid = fopen(OUTPUT_FILENAME_FREQ,"w");
fprintf(fid,"# %s: auto-generated file\n", OUTPUT_FILENAME_FREQ);
fprintf(fid,"#\n");
fprintf(fid,"# nfft = %u\n", nfft);
fprintf(fid,"# %12s %12s %12s %12s\n", "freq", "PSD [dB]", "filter [dB]", "error [dB]");
// save input and output arrays
for (i=0; i<nfft; i++) {
float f = (float)i/(float)nfft - 0.5f;
unsigned int k = (i + nfft/2)%nfft;
fprintf(fid," %12.8f %12.8f %12.8f %12.8f\n",
f,
20*log10f(cabsf(y_freq[k])),
20*log10f(cabsf(h_freq[k])),
20*log10f(cabsf(e_freq[k])));
}
fclose(fid);
printf("results written to '%s'\n", OUTPUT_FILENAME_FREQ);
printf("done.\n");
return 0;
}
