int main(int argc, char*argv[])
{
srand(time(NULL));
// options
unsigned int k=2; // filter samples/symbol
unsigned int m=5; // filter delay (symbols)
float beta=0.3f; // bandwidth-time product
float dt = 0.0f; // fractional sample timing offset
unsigned int num_sync_symbols = 64; // number of synchronization symbols
float SNRdB = 20.0f; // signal-to-noise ratio [dB]
float dphi = 0.02f; // carrier frequency offset
float phi = 2*M_PI*randf(); // carrier phase offset
int dopt;
while ((dopt = getopt(argc,argv,"uhk:m:n:b:t:F:t:S:")) != EOF) {
switch (dopt) {
case 'h': usage(); return 0;
case 'k': k = atoi(optarg); break;
case 'm': m = atoi(optarg); break;
case 'n': num_sync_symbols = atoi(optarg); break;
case 'b': beta = atof(optarg); break;
case 'F': dphi = atof(optarg); break;
case 't': dt = atof(optarg); break;
case 'S': SNRdB = atof(optarg); break;
default:
exit(1);
}
}
unsigned int i;
// validate input
if (beta <= 0.0f || beta >= 1.0f) {
fprintf(stderr,"error: %s, bandwidth-time product must be in (0,1)\n", argv[0]);
exit(1);
} else if (dt < -0.5f || dt > 0.5f) {
fprintf(stderr,"error: %s, fractional sample offset must be in [-0.5,0.5]\n", argv[0]);
exit(1);
}
// derived values
unsigned int num_symbols = num_sync_symbols + 2*m + 10;
unsigned int num_samples = k*num_symbols;
float nstd = powf(10.0f, -SNRdB/20.0f);
// arrays
float complex seq[num_sync_symbols]; // synchronization pattern (symbols)
float complex s0[k*num_sync_symbols]; // synchronization pattern (samples)
float complex x[num_samples]; // transmitted signal
float complex y[num_samples]; // received signal
float complex rxy[num_samples]; // pre-demod correlation output
float dphi_hat[num_samples]; // carrier offset estimate
// create transmit/receive interpolator/decimator
firinterp_crcf interp = firinterp_crcf_create_prototype(LIQUID_FIRFILT_RRC,k,m,beta,dt);
// generate synchronization pattern (BPSK) and interpolate
for (i=0; i<num_sync_symbols + 2*m; i++) {
float complex sym = 0.0f;
if (i < num_sync_symbols) {
sym = rand() % 2 ? -1.0f : 1.0f;
seq[i] = sym;
}
if (i < 2*m) firinterp_crcf_execute(interp, sym, s0);
else firinterp_crcf_execute(interp, sym, &s0[k*(i-2*m)]);
}
// reset interpolator
firinterp_crcf_reset(interp);
// interpolate input
for (i=0; i<num_symbols; i++) {
float complex sym = i < num_sync_symbols ? seq[i] : 0.0f;
firinterp_crcf_execute(interp, sym, &x[k*i]);
}
// push through channel
for (i=0; i<num_samples; i++)
y[i] = x[i]*cexpf(_Complex_I*(dphi*i + phi)) + nstd*(randnf() + _Complex_I*randnf())*M_SQRT1_2;
// create cross-correlator
bpresync_cccf sync = bpresync_cccf_create(s0, k*num_sync_symbols, 0.05f, 11);
bpresync_cccf_print(sync);
// push signal through cross-correlator
float rxy_max = 0.0f; // maximum cross-correlation
float dphi_est = 0.0f; // carrier frequency offset estimate
int delay_est = 0; // delay estimate
for (i=0; i<num_samples; i++) {
// correlate
bpresync_cccf_push(sync, y[i]);
bpresync_cccf_execute(sync, &rxy[i], &dphi_hat[i]);
// detect...
if (cabsf(rxy[i]) > 0.6f) {
printf("****** preamble found, rxy = %12.8f (dphi-hat: %12.8f), i=%3u ******\n",
cabsf(rxy[i]), dphi_hat[i], i);
}
// retain maximum
if (cabsf(rxy[i]) > rxy_max) {
rxy_max = cabsf(rxy[i]);
dphi_est = dphi_hat[i];
delay_est = (int)i - (int)2*k*m + 1;
}
}
// destroy objects
firinterp_crcf_destroy(interp);
bpresync_cccf_destroy(sync);
// print results
printf("\n");
printf("rxy (max) : %12.8f\n", rxy_max);
printf("dphi est. : %12.8f ,error=%12.8f\n", dphi_est, dphi-dphi_est);
printf("delay est.: %12d ,error=%3d sample(s)\n", delay_est, k*num_sync_symbols - delay_est);
printf("\n");
//
// export results
//
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");
fprintf(fid,"num_samples = %u;\n", num_samples);
fprintf(fid,"num_symbols = %u;\n", num_symbols);
fprintf(fid,"k = %u;\n", k);
fprintf(fid,"x = zeros(1,num_samples);\n");
fprintf(fid,"y = zeros(1,num_samples);\n");
fprintf(fid,"rxy = zeros(1,num_samples);\n");
for (i=0; i<num_samples; i++) {
fprintf(fid,"x(%4u) = %12.8f + j*%12.8f;\n", i+1, crealf(x[i]), cimagf(x[i]));
fprintf(fid,"y(%4u) = %12.8f + j*%12.8f;\n", i+1, crealf(y[i]), cimagf(y[i]));
fprintf(fid,"rxy(%4u) = %12.8f + j*%12.8f;\n", i+1, crealf(rxy[i]), cimagf(rxy[i]));
}
fprintf(fid,"t=[0:(num_samples-1)]/k;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(t,real(y), t,imag(y));\n");
fprintf(fid," axis([0 num_symbols -2 2]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('received signal');\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(t,abs(rxy));\n");
fprintf(fid," axis([0 num_symbols 0 1.5]);\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('correlator output');\n");
fprintf(fid," grid on;\n");
fclose(fid);
printf("results written to '%s'\n", OUTPUT_FILENAME);
return 0;
}
int main(int argc, char*argv[])
{
// options
float noise_floor= -40.0f; // noise floor [dB]
float SNRdB = 20.0f; // signal-to-noise ratio [dB]
float bt = 0.05f; // loop bandwidth
unsigned int num_symbols= 100; // number of iterations
unsigned int d = 5; // print every d iterations
unsigned int k = 2; // interpolation factor (samples/symbol)
unsigned int m = 3; // filter delay (symbols)
float beta = 0.3f; // filter excess bandwidth factor
float dt = 0.0f; // filter fractional sample delay
// derived values
unsigned int num_samples=num_symbols*k;
float gamma = powf(10.0f, (SNRdB+noise_floor)/20.0f); // channel gain
float nstd = powf(10.0f, noise_floor / 20.0f);
// arrays
float complex x[num_samples];
float complex y[num_samples];
float rssi[num_samples];
// create objects
modem mod = modem_create(LIQUID_MODEM_QPSK);
firinterp_crcf interp = firinterp_crcf_create_prototype(LIQUID_FIRFILT_RRC,k,m,beta,dt);
agc_crcf p = agc_crcf_create();
agc_crcf_set_bandwidth(p, bt);
unsigned int i;
// print info
printf("automatic gain control // loop bandwidth: %4.2e\n",bt);
unsigned int sym;
float complex s;
for (i=0; i<num_symbols; i++) {
// generate random symbol
sym = modem_gen_rand_sym(mod);
modem_modulate(mod, sym, &s);
s *= gamma;
firinterp_crcf_execute(interp, s, &x[i*k]);
}
// add noise
for (i=0; i<num_samples; i++)
x[i] += nstd*(randnf() + _Complex_I*randnf()) * M_SQRT1_2;
// run agc
for (i=0; i<num_samples; i++) {
agc_crcf_execute(p, x[i], &y[i]);
rssi[i] = agc_crcf_get_rssi(p);
}
// destroy objects
modem_destroy(mod);
agc_crcf_destroy(p);
firinterp_crcf_destroy(interp);
// print results to screen
printf("received signal strength indication (rssi):\n");
for (i=0; i<num_samples; i+=d) {
printf("%4u : %8.2f\n", i, rssi[i]);
}
//
// export results
//
FILE* fid = fopen(OUTPUT_FILENAME,"w");
if (!fid) {
fprintf(stderr,"error: %s, could not open '%s' for writing\n", argv[0], OUTPUT_FILENAME);
exit(1);
}
fprintf(fid,"%% %s: auto-generated file\n\n",OUTPUT_FILENAME);
fprintf(fid,"n = %u;\n", num_samples);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n\n");
for (i=0; i<num_samples; i++) {
fprintf(fid," x(%4u) = %12.4e + j*%12.4e;\n", i+1, crealf(x[i]), cimagf(x[i]));
fprintf(fid," y(%4u) = %12.4e + j*%12.4e;\n", i+1, crealf(y[i]), cimagf(y[i]));
fprintf(fid,"rssi(%4u) = %12.4e;\n", i+1, rssi[i]);
}
fprintf(fid,"\n\n");
fprintf(fid,"n = length(x);\n");
fprintf(fid,"t = 0:(n-1);\n");
fprintf(fid,"figure('position',[100 100 800 600]);\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(t,rssi,'-k','LineWidth',2);\n");
fprintf(fid," xlabel('sample index');\n");
fprintf(fid," ylabel('rssi [dB]');\n");
fprintf(fid," grid on;\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(t,real(y),t,imag(y));\n");
fprintf(fid," xlabel('sample index');\n");
fprintf(fid," ylabel('agc output');\n");
fprintf(fid," grid on;\n");
fclose(fid);
printf("results written to %s\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
int main(int argc, char*argv[]) {
// options
unsigned int k=4; // samples/symbol
unsigned int m=3; // filter delay
float As = 60.0f; // filter stop-band attenuation
unsigned int num_data_symbols=16; // number of data symbols
int dopt;
while ((dopt = getopt(argc,argv,"uhk:m:s:n:")) != EOF) {
switch (dopt) {
case 'u':
case 'h': usage(); return 0;
case 'k': k = atoi(optarg); break;
case 'm': m = atoi(optarg); break;
case 's': As = atof(optarg); break;
case 'n': num_data_symbols = atoi(optarg); break;
default:
exit(1);
}
}
// validate options
if (k < 2) {
fprintf(stderr,"error: %s, interp factor must be greater than 1\n", argv[0]);
exit(1);
} else if (m < 1) {
fprintf(stderr,"error: %s, filter delay must be greater than 0\n", argv[0]);
exit(1);
} else if (num_data_symbols < 1) {
fprintf(stderr,"error: %s, must have at least one data symbol\n", argv[0]);
usage();
return 1;
}
// derived values
unsigned int num_symbols = num_data_symbols + 2*m; // compensate for filter delay
unsigned int num_samples = k*num_symbols;
// create interpolator from prototype
firinterp_crcf q = firinterp_crcf_create_prototype(k,m,As);
// generate input signal and interpolate
float complex x[num_symbols]; // input symbols
float complex y[num_samples]; // output samples
unsigned int i;
for (i=0; i<num_data_symbols; i++) {
x[i] = (rand() % 2 ? 1.0f : -1.0f) +
(rand() % 2 ? 1.0f : -1.0f) * _Complex_I;
}
// pad end of sequence with zeros
for (i=num_data_symbols; i<num_symbols; i++)
x[i] = 0.0f;
// interpolate symbols
for (i=0; i<num_symbols; i++)
firinterp_crcf_execute(q, x[i], &y[k*i]);
// destroy interpolator object
firinterp_crcf_destroy(q);
// print results to screen
printf("x(t) :\n");
for (i=0; i<num_symbols; i++)
printf(" x(%4u) = %8.4f + j*%8.4f;\n", i, crealf(x[i]), cimagf(x[i]));
printf("y(t) :\n");
for (i=0; i<num_samples; i++) {
printf(" y(%4u) = %8.4f + j*%8.4f;", i, crealf(y[i]), cimagf(y[i]));
if ( (i >= k*m) && ((i%k)==0))
printf(" **\n");
else
printf("\n");
}
//
// export output file
//
FILE * fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n");
fprintf(fid,"k = %u;\n", k);
fprintf(fid,"m = %u;\n", m);
fprintf(fid,"num_symbols = %u;\n", num_symbols);
fprintf(fid,"num_samples = k*num_symbols;\n");
fprintf(fid,"x = zeros(1,num_symbols);\n");
fprintf(fid,"y = zeros(1,num_samples);\n");
for (i=0; i<num_symbols; i++)
fprintf(fid,"x(%4u) = %12.4e + j*%12.4e;\n", i+1, crealf(x[i]), cimagf(x[i]));
for (i=0; i<num_samples; i++)
fprintf(fid,"y(%4u) = %12.4e + j*%12.4e;\n", i+1, crealf(y[i]), cimagf(y[i]));
fprintf(fid,"\n\n");
fprintf(fid,"tx = [0:(num_symbols-1)];\n");
fprintf(fid,"ty = [0:(num_samples-1)]/k - m;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(ty,real(y),'-',tx,real(x),'s');\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('real');\n");
fprintf(fid," grid on;\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(ty,imag(y),'-',tx,imag(x),'s');\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('imag');\n");
fprintf(fid," grid on;\n");
fclose(fid);
printf("results written to %s.\n",OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
//
// AUTOTEST: static channel filter, blind equalization on QPSK symbols
//
void autotest_eqlms_cccf_blind()
{
// parameters
float tol = 2e-2f; // error tolerance
unsigned int k = 2; // samples/symbol
unsigned int m = 7; // filter delay
float beta = 0.3f; // excess bandwidth factor
unsigned int p = 7; // equalizer order
float mu = 0.7f; // equalizer bandwidth
unsigned int num_symbols = 400; // number of symbols to observe
// create sequence generator for repeatability
msequence ms = msequence_create_default(12);
// create interpolating filter
firinterp_crcf interp = firinterp_crcf_create_prototype(LIQUID_FIRFILT_ARKAISER,k,m,beta,0);
// create equalizer
eqlms_cccf eq = eqlms_cccf_create_rnyquist(LIQUID_FIRFILT_ARKAISER,k,p,beta,0);
eqlms_cccf_set_bw(eq, mu);
// create channel filter
float complex h[5] = {
{ 1.00f, 0.00f},
{ 0.00f, -0.01f},
{-0.11f, 0.02f},
{ 0.02f, 0.01f},
{-0.09f, -0.04f} };
firfilt_cccf fchannel = firfilt_cccf_create(h,5);
// arrays
float complex buf[k]; // filter buffer
float complex sym_in [num_symbols]; // input symbols
float complex sym_out[num_symbols]; // equalized symbols
// run equalization
unsigned int i;
unsigned int j;
for (i=0; i<num_symbols; i++) {
// generate input symbol
sym_in[i] = ( msequence_advance(ms) ? M_SQRT1_2 : -M_SQRT1_2 ) +
( msequence_advance(ms) ? M_SQRT1_2 : -M_SQRT1_2 ) * _Complex_I;
// interpolate
firinterp_crcf_execute(interp, sym_in[i], buf);
// apply channel filter (in place)
firfilt_cccf_execute_block(fchannel, buf, k, buf);
// apply equalizer as filter
for (j=0; j<k; j++) {
eqlms_cccf_push(eq, buf[j]);
// decimate by k
if ( (j%k) != 0 ) continue;
eqlms_cccf_execute(eq, &sym_out[i]);
// update equalization (blind operation)
if (i > m + p)
eqlms_cccf_step(eq, sym_out[i]/cabsf(sym_out[i]), sym_out[i]);
}
}
// compare input, output
unsigned int settling_delay = 285;
for (i=m+p; i<num_symbols; i++) {
// compensate for delay
j = i-m-p;
// absolute error
float error = cabsf(sym_in[j]-sym_out[i]);
if (liquid_autotest_verbose) {
printf("x[%3u] = {%12.8f,%12.8f}, y[%3u] = {%12.8f,%12.8f}, error=%12.8f %s\n",
j, crealf(sym_in [j]), cimagf(sym_in [j]),
i, crealf(sym_out[i]), cimagf(sym_out[i]),
error, error > tol ? "*" : "");
if (i == settling_delay + m + p)
printf("--- start of test ---\n");
}
// check error
if (i > settling_delay + m + p)
CONTEND_DELTA(error, 0.0f, tol);
}
// clean up objects
firfilt_cccf_destroy(fchannel);
eqlms_cccf_destroy(eq);
msequence_destroy(ms);
}
int main(int argc, char*argv[])
{
srand(time(NULL));
// options
unsigned int k=2; // filter samples/symbol
unsigned int m=4; // filter delay (symbols)
float beta=0.3f; // bandwidth-time product
float dt = 0.0f; // fractional sample timing offset
unsigned int num_sync_symbols = 64; // number of data symbols
float SNRdB = 30.0f; // signal-to-noise ratio [dB]
float dphi = 0.0f; // carrier frequency offset
float phi = 0.0f; // carrier phase offset
unsigned int num_delay_symbols = 12;
unsigned int num_dphi_hat = 21; // number of frequency offset estimates
float dphi_hat_step = 0.01f; // frequency offset step size
int dopt;
while ((dopt = getopt(argc,argv,"uhk:m:n:b:t:F:P:s:")) != EOF) {
switch (dopt) {
case 'h': usage(); return 0;
case 'k': k = atoi(optarg); break;
case 'm': m = atoi(optarg); break;
case 'n': num_sync_symbols = atoi(optarg); break;
case 'b': beta = atof(optarg); break;
case 't': dt = atof(optarg); break;
case 'F': dphi = atof(optarg); break;
case 'P': phi = atof(optarg); break;
case 's': SNRdB = atof(optarg); break;
default:
exit(1);
}
}
unsigned int i;
// validate input
if (beta <= 0.0f || beta >= 1.0f) {
fprintf(stderr,"error: %s, bandwidth-time product must be in (0,1)\n", argv[0]);
exit(1);
} else if (dt < -0.5 || dt > 0.5) {
fprintf(stderr,"error: %s, fractional sample offset must be in (0,1)\n", argv[0]);
exit(1);
}
// derived values
unsigned int num_symbols = num_delay_symbols + num_sync_symbols + 2*m;
unsigned int num_samples = k*num_symbols;
unsigned int num_sync_samples = k*num_sync_symbols;
float nstd = powf(10.0f, -SNRdB/20.0f);
// arrays
float complex seq[num_sync_symbols]; // data sequence (symbols)
float complex s0[num_sync_samples]; // data sequence (interpolated samples)
float complex x[num_samples]; // transmitted signal
float complex y[num_samples]; // received signal
float rxy[num_dphi_hat][num_samples]; // pre-demod output matrix
// generate sequence
for (i=0; i<num_sync_symbols; i++) {
float sym_i = rand() % 2 ? M_SQRT1_2 : -M_SQRT1_2;
float sym_q = rand() % 2 ? M_SQRT1_2 : -M_SQRT1_2;
seq[i] = sym_i + _Complex_I*sym_q;
}
// create interpolated sequence, compensating for filter delay
firinterp_crcf interp_seq = firinterp_crcf_create_prototype(LIQUID_FIRFILT_RRC,k,m,beta,0.0f);
for (i=0; i<num_sync_symbols+m; i++) {
if (i < m) firinterp_crcf_execute(interp_seq, seq[i], &s0[0]);
else if (i < num_sync_symbols) firinterp_crcf_execute(interp_seq, seq[i], &s0[k*(i-m)]);
else firinterp_crcf_execute(interp_seq, 0, &s0[k*(i-m)]);
}
firinterp_crcf_destroy(interp_seq);
// compute g = E{ |s0|^2 }
float g = 0.0f;
for (i=0; i<num_sync_samples; i++)
g += crealf( s0[i]*conjf(s0[i]) );
// create transmit interpolator and generate sequence
firinterp_crcf interp_tx = firinterp_crcf_create_prototype(LIQUID_FIRFILT_RRC,k,m,beta,dt);
unsigned int n=0;
for (i=0; i<num_delay_symbols; i++) {
firinterp_crcf_execute(interp_tx, 0, &x[k*n]);
n++;
}
for (i=0; i<num_sync_symbols; i++) {
firinterp_crcf_execute(interp_tx, seq[i], &x[k*n]);
n++;
}
for (i=0; i<2*m; i++) {
firinterp_crcf_execute(interp_tx, 0, &x[k*n]);
n++;
}
assert(n==num_symbols);
firinterp_crcf_destroy(interp_tx);
// add channel impairments
for (i=0; i<num_samples; i++) {
y[i] = x[i]*cexp(_Complex_I*(dphi*i + phi)) + nstd*( randnf() + _Complex_I*randnf() );
}
float complex z; // filter output sample
for (n=0; n<num_dphi_hat; n++) {
float dphi_hat = ((float)n - 0.5*(float)(num_dphi_hat-1)) * dphi_hat_step;
printf(" dphi_hat : %12.8f\n", dphi_hat);
// create flipped, conjugated coefficients
float complex s1[num_sync_samples];
for (i=0; i<num_sync_samples; i++)
s1[i] = conjf( s0[num_sync_samples-i-1]*cexpf(_Complex_I*(dphi_hat*i)) );
// create matched filter and detect signal
firfilt_cccf fsync = firfilt_cccf_create(s1, num_sync_samples);
for (i=0; i<num_samples; i++) {
firfilt_cccf_push(fsync, y[i]);
firfilt_cccf_execute(fsync, &z);
rxy[n][i] = cabsf(z) / g;
}
// destroy filter
firfilt_cccf_destroy(fsync);
}
// print results
//printf("rxy (max) : %12.8f\n", rxy_max);
//
// export results
//
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");
fprintf(fid,"k = %u;\n", k);
fprintf(fid,"m = %u;\n", m);
fprintf(fid,"beta = %f;\n", beta);
fprintf(fid,"num_sync_symbols = %u;\n", num_sync_symbols);
fprintf(fid,"num_sync_samples = k*num_sync_symbols;\n");
fprintf(fid,"num_symbols = %u;\n", num_symbols);
fprintf(fid,"num_samples = %u;\n", num_samples);
fprintf(fid,"num_dphi_hat = %u;\n", num_dphi_hat);
fprintf(fid,"dphi_hat_step = %f;\n", dphi_hat_step);
// save sequence symbols
fprintf(fid,"seq = zeros(1,num_sync_symbols);\n");
for (i=0; i<num_sync_symbols; i++)
fprintf(fid,"seq(%4u) = %12.8f + j*%12.8f;\n", i+1, crealf(seq[i]), cimagf(seq[i]));
// save interpolated sequence
fprintf(fid,"s = zeros(1,num_sync_samples);\n");
for (i=0; i<num_sync_samples; i++)
fprintf(fid,"s(%4u) = %12.8f + j*%12.8f;\n", i+1, crealf(s0[i]), cimagf(s0[i]));
fprintf(fid,"x = zeros(1,num_samples);\n");
fprintf(fid,"y = zeros(1,num_samples);\n");
for (i=0; i<num_samples; i++) {
fprintf(fid,"x(%6u) = %12.8f + j*%12.8f;\n", i+1, crealf(x[i]), cimagf(x[i]));
fprintf(fid,"y(%6u) = %12.8f + j*%12.8f;\n", i+1, crealf(y[i]), cimagf(y[i]));
}
// save cross-correlation output
fprintf(fid,"rxy = zeros(num_dphi_hat,num_samples);\n");
for (n=0; n<num_dphi_hat; n++) {
for (i=0; i<num_samples; i++) {
fprintf(fid,"rxy(%6u,%6u) = %12.8f;\n", n+1, i+1, rxy[n][i]);
}
}
fprintf(fid,"t=[0:(num_samples-1)]/k;\n");
fprintf(fid,"figure;\n");
fprintf(fid,"plot(1:length(s),real(s), 1:length(s),imag(s));\n");
fprintf(fid,"dphi_hat = ( [0:(num_dphi_hat-1)] - (num_dphi_hat-1)/2 ) * dphi_hat_step;\n");
fprintf(fid,"mesh(dphi_hat, t, rxy');\n");
#if 0
fprintf(fid,"z = abs( z );\n");
fprintf(fid,"[zmax i] = max(z);\n");
fprintf(fid,"plot(1:length(z),z,'-x');\n");
fprintf(fid,"axis([(i-8*k) (i+8*k) 0 zmax*1.2]);\n");
fprintf(fid,"grid on\n");
#endif
fclose(fid);
printf("results written to '%s'\n", OUTPUT_FILENAME);
return 0;
}
