// Helper function to keep code base small
void fec_test_codec(fec_scheme _fs, unsigned int _n, void * _opts)
{
#if !LIBFEC_ENABLED
if ( _fs == LIQUID_FEC_CONV_V27 ||
_fs == LIQUID_FEC_CONV_V29 ||
_fs == LIQUID_FEC_CONV_V39 ||
_fs == LIQUID_FEC_CONV_V615 ||
_fs == LIQUID_FEC_CONV_V27P23 ||
_fs == LIQUID_FEC_CONV_V27P34 ||
_fs == LIQUID_FEC_CONV_V27P45 ||
_fs == LIQUID_FEC_CONV_V27P56 ||
_fs == LIQUID_FEC_CONV_V27P67 ||
_fs == LIQUID_FEC_CONV_V27P78 ||
_fs == LIQUID_FEC_CONV_V29P23 ||
_fs == LIQUID_FEC_CONV_V29P34 ||
_fs == LIQUID_FEC_CONV_V29P45 ||
_fs == LIQUID_FEC_CONV_V29P56 ||
_fs == LIQUID_FEC_CONV_V29P67 ||
_fs == LIQUID_FEC_CONV_V29P78 ||
_fs == LIQUID_FEC_RS_M8)
{
AUTOTEST_WARN("convolutional, Reed-Solomon codes unavailable (install libfec)\n");
return;
}
#endif
// generate fec object
fec q = fec_create(_fs,_opts);
// create arrays
unsigned int n_enc = fec_get_enc_msg_length(_fs,_n);
unsigned char msg[_n]; // original message
unsigned char msg_enc[n_enc]; // encoded message
unsigned char msg_dec[_n]; // decoded message
// initialze message
unsigned int i;
for (i=0; i<_n; i++) {
msg[i] = rand() & 0xff;
msg_dec[i] = 0;
}
// encode message
fec_encode(q,_n,msg,msg_enc);
// channel: add single error
msg_enc[0] ^= 0x01;
// decode message
fec_decode(q,_n,msg_enc,msg_dec);
// validate output
CONTEND_SAME_DATA(msg,msg_dec,_n);
// clean up objects
fec_destroy(q);
}
// Helper function to keep code base small
void modem_test_demodstats(modulation_scheme _ms)
{
// generate mod/demod
modem mod = modem_create(_ms);
modem demod = modem_create(_ms);
// run the test
unsigned int i, s, M = 1 << modem_get_bps(mod);
float complex x;
float complex x_hat; // rotated symbol
float demodstats;
float phi = 0.01f;
for (i=0; i<M; i++) {
// reset modem objects
modem_reset(mod);
modem_reset(demod);
// modulate symbol
modem_modulate(mod, i, &x);
// ignore rare condition where modulated symbol is (0,0)
// (e.g. APSK-8)
if (cabsf(x) < 1e-3f) continue;
// add phase offsets
x_hat = x * cexpf( phi*_Complex_I);
// demod positive phase signal, and ensure demodulator
// maps to appropriate symbol
modem_demodulate(demod, x_hat, &s);
if (s != i)
AUTOTEST_WARN("modem_test_demodstats(), output symbol does not match");
demodstats = modem_get_demodulator_phase_error(demod);
CONTEND_EXPRESSION(demodstats > 0.0f);
}
// repeat with negative phase error
for (i=0; i<M; i++) {
// reset modem objects
modem_reset(mod);
modem_reset(demod);
// modulate symbol
modem_modulate(mod, i, &x);
// ignore rare condition where modulated symbol is (0,0)
// (e.g. APSK-8)
if (cabsf(x) < 1e-3f) continue;
// add phase offsets
x_hat = x * cexpf(-phi*_Complex_I);
// demod positive phase signal, and ensure demodulator
// maps to appropriate symbol
modem_demodulate(demod, x_hat, &s);
if (s != i)
AUTOTEST_WARN("modem_test_demodstats(), output symbol does not match");
demodstats = modem_get_demodulator_phase_error(demod);
CONTEND_EXPRESSION(demodstats < 0.0f);
}
// clean up allocated objects up
modem_destroy(mod);
modem_destroy(demod);
}
