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Diffstat (limited to 'unittest/freedv_700d_comprx.c')
| -rw-r--r-- | unittest/freedv_700d_comprx.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/unittest/freedv_700d_comprx.c b/unittest/freedv_700d_comprx.c new file mode 100644 index 0000000..0cf8407 --- /dev/null +++ b/unittest/freedv_700d_comprx.c @@ -0,0 +1,140 @@ +/*---------------------------------------------------------------------------*\ + + FILE........: freedv_700d_comprx.c + AUTHOR......: David Rowe + DATE CREATED: July 2022 + + Complex valued rx to support ctests. Includes a few operations that will + only work if complex Tx and Rx signals are being handled correctly. + +\*---------------------------------------------------------------------------*/ + +#include <assert.h> +#include <stdio.h> +#include <stdlib.h> + +#include "codec2_cohpsk.h" +#include "comp_prim.h" +#include "freedv_api.h" +#include "freedv_api_internal.h" +#include "ofdm_internal.h" + +int main(int argc, char *argv[]) { + /* with no arguments then run with no test code */ + int test_num = 0; + if (argc == 2) { + if (strcmp(argv[1], "tx") == 0) { + test_num = 1; + } + if (strcmp(argv[1], "rx") == 0) { + test_num = 2; + } + } + fprintf(stderr, "%d\n", test_num); + + struct freedv *freedv; + freedv = freedv_open(FREEDV_MODE_700D); + assert(freedv != NULL); + + /* note API functions to tell us how big our buffers need to be */ + short speech_out[freedv_get_n_max_speech_samples(freedv)]; + short demod_in[2 * freedv_get_n_max_modem_samples(freedv)]; + COMP demod_in_comp[2 * freedv_get_n_max_modem_samples(freedv)]; + + /* set up small freq offset */ + float foff_hz = 25; + COMP phase_ch; + phase_ch.real = 1.0; + phase_ch.imag = 0.0; + + /* set complex sine wave interferer at -fc */ + COMP interferer_phase = {1.0, 0.0}; + COMP interferer_freq; + interferer_freq.real = + cos(2.0 * M_PI * freedv->ofdm->tx_centre / FREEDV_FS_8000); + interferer_freq.imag = + sin(2.0 * M_PI * freedv->ofdm->tx_centre / FREEDV_FS_8000); + interferer_freq = cconj(interferer_freq); + + /* log a file of demod input samples for plotting in Octave */ + FILE *fdemod = fopen("demod.f32", "wb"); + assert(fdemod != NULL); + + /* measure demod input power, interferer input power */ + float power_d = 0.0; + float power_interferer = 0.0; + + int frames = 0, sum_sync = 0, frames_snr = 0; + float sum_snr = 0.0; + size_t nin, nout; + nin = freedv_nin(freedv); + + while (fread(demod_in, sizeof(short), 2 * nin, stdin) == 2 * nin) { + for (int i = 0; i < nin; i++) { + demod_in_comp[i].real = (float)demod_in[2 * i]; + demod_in_comp[i].imag = (float)demod_in[2 * i + 1]; + // demod_in_comp[i].imag = 0; + } + + if (test_num == 1) { + /* So Tx is a complex OFDM signal centered at +fc. A small + shift fd followed by Re{} will only work if Tx is complex. + If Tx is real, neg freq components at -fc+fd will be + aliased on top of fc+fd wanted signal by Re{} operation. + This can be tested by setting demod_in_comp[i].imag = 0 + above */ + fdmdv_freq_shift_coh(demod_in_comp, demod_in_comp, foff_hz, + FREEDV_FS_8000, &phase_ch, nin); + for (int i = 0; i < nin; i++) demod_in_comp[i].imag = 0.0; + } + + if (test_num == 2) { + /* a complex sinewave (carrier) at -fc will only be ignored if + Rx is treating signal as complex, otherwise if real a +fc + alias will appear in the middle of our wanted signal at + +fc, this can be tested by setting demod_in_comp[i].imag = + 0 below */ + for (int i = 0; i < nin; i++) { + COMP a = fcmult(2E4, interferer_phase); + interferer_phase = cmult(interferer_phase, interferer_freq); + power_interferer += a.real * a.real + a.imag * a.imag; + COMP d = demod_in_comp[i]; + power_d += d.real * d.real + d.imag * d.imag; + demod_in_comp[i] = cadd(d, a); + // demod_in_comp[i].imag = 0; + } + } + + /* useful to take a look at this with Octave */ + fwrite(demod_in_comp, sizeof(COMP), nin, fdemod); + + nout = freedv_comprx(freedv, speech_out, demod_in_comp); + nin = freedv_nin(freedv); /* call me on every loop! */ + fwrite(speech_out, sizeof(short), nout, stdout); + int sync; + float snr_est; + freedv_get_modem_stats(freedv, &sync, &snr_est); + fprintf(stderr, "sync: %d snr_est: %f\n", sync, snr_est); + frames++; + sum_sync += sync; + if (sync) { + sum_snr += snr_est; + frames_snr++; + } + } + + fclose(fdemod); + freedv_close(freedv); + + if (test_num == 2) + fprintf(stderr, "Demod/Interferer power ratio: %3.2f dB\n", + 10 * log10(power_d / power_interferer)); + float snr_av = sum_snr / frames_snr; + fprintf(stderr, "frames: %d sum_sync: %d snr_av: %3.2f dB\n", frames, + sum_sync, snr_av); + + if (snr_av > 8.0) + return 0; + else + return 1; +} |