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CubicSDR
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Experimenting with improving SSB

This commit is contained in:
Charles J. Cliffe 2015-02-12 01:38:53 -05:00
parent 85fd266890
commit 4f47fa7375
1 changed files with 39 additions and 27 deletions
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66
src/demod/DemodulatorThread.cpp
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@ -14,8 +14,8 @@ DemodulatorThread::DemodulatorThread(DemodulatorThreadPostInputQueue* iqInputQue
0), squelchEnabled(false) {
demodFM = freqdem_create(0.5);
demodAM_USB = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_LSB, 1);
demodAM_LSB = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_USB, 1);
demodAM_USB = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_USB, 1);
demodAM_LSB = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_LSB, 1);
demodAM_DSB = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_DSB, 1);
demodAM_DSB_CSP = ampmodem_create(0.5, 0.0, LIQUID_AMPMODEM_DSB, 0);
demodAM = demodAM_DSB_CSP;
@ -64,7 +64,8 @@ void DemodulatorThread::threadMain() {
delete h;
liquid_float_complex x, y;
liquid_float_complex x, y, z[2];
float rz[2];
firhilbf firStereoR2C = firhilbf_create(5, 60.0f);
firhilbf firStereoC2R = firhilbf_create(5, 60.0f);
@ -79,16 +80,20 @@ void DemodulatorThread::threadMain() {
nco_crcf ssbShifterDown = nco_crcf_create(LIQUID_NCO);
nco_crcf_set_frequency(ssbShifterDown, (2.0 * M_PI) * 0.25);
float ssbFt = 0.001f; // filter transition
float ssbAs = 120.0f; // stop-band attenuation [dB]
// float ssbFt = 0.001f; // filter transition
// float ssbAs = 120.0f; // stop-band attenuation [dB]
h_len = estimate_req_filter_len(ssbFt, ssbAs);
float *ssb_h = new float[h_len];
liquid_firdes_kaiser(h_len, 0.25, ssbAs, 0.0, ssb_h);
// h_len = estimate_req_filter_len(ssbFt, ssbAs);
// float *ssb_h = new float[h_len];
// liquid_firdes_kaiser(h_len, 0.25, ssbAs, 0.0, ssb_h);
firfilt_crcf firSSB = firfilt_crcf_create(ssb_h, h_len);
// firfilt_crcf firSSB = firfilt_crcf_create(ssb_h, h_len);
delete ssb_h;
// delete ssb_h;
// create half-band resampler
resamp2_crcf ssbInterp = resamp2_crcf_create(7,0.0f,-120.0f);
resamp2_rrrf ssbDecim = resamp2_rrrf_create(7,0.0f,-120.0f);
// Automatic IQ gain
iqAutoGain = agc_crcf_create();
@ -175,6 +180,8 @@ void DemodulatorThread::threadMain() {
currentSignalLevel = agc_crcf_get_signal_level(iqAutoGain);
}
amOutputCeil = 0;
if (demodulatorType == DEMOD_TYPE_FM) {
freqdem_demodulate_block(demodFM, &agcData[0], bufSize, &demodOutputData[0]);
} else {
@ -182,22 +189,34 @@ void DemodulatorThread::threadMain() {
switch (demodulatorType.load()) {
case DEMOD_TYPE_LSB:
for (int i = 0; i < bufSize; i++) { // Reject upper band
nco_crcf_mix_up(ssbShifterUp, inp->data[i], &x);
nco_crcf_step(ssbShifterUp);
firfilt_crcf_push(firSSB, x);
firfilt_crcf_execute(firSSB, &x);
nco_crcf_mix_down(ssbShifterDown, x, &(inp->data[i]));
resamp2_crcf_interp_execute(ssbInterp, inp->data[i], z);
nco_crcf_mix_down(ssbShifterDown, z[0], &y);
nco_crcf_step(ssbShifterDown);
ampmodem_demodulate(demodAM, y, &rz[0]);
nco_crcf_mix_down(ssbShifterDown, z[1], &y);
nco_crcf_step(ssbShifterDown);
ampmodem_demodulate(demodAM, y, &rz[1]);
resamp2_rrrf_decim_execute(ssbDecim, rz, &demodOutputData[i]);
if (demodOutputData[i] > amOutputCeil) {
amOutputCeil = demodOutputData[i];
}
}
break;
case DEMOD_TYPE_USB:
for (int i = 0; i < bufSize; i++) { // Reject lower band
nco_crcf_mix_down(ssbShifterDown, inp->data[i], &x);
nco_crcf_step(ssbShifterDown);
firfilt_crcf_push(firSSB, x);
firfilt_crcf_execute(firSSB, &x);
nco_crcf_mix_up(ssbShifterUp, x, &(inp->data[i]));
resamp2_crcf_interp_execute(ssbInterp, inp->data[i], z);
nco_crcf_mix_up(ssbShifterUp, z[0], &y);
nco_crcf_step(ssbShifterUp);
ampmodem_demodulate(demodAM, y, &rz[0]);
nco_crcf_mix_up(ssbShifterUp, z[1], &y);
nco_crcf_step(ssbShifterUp);
ampmodem_demodulate(demodAM, y, &rz[1]);
resamp2_rrrf_decim_execute(ssbDecim, rz, &demodOutputData[i]);
if (demodOutputData[i] > amOutputCeil) {
amOutputCeil = demodOutputData[i];
}
}
break;
case DEMOD_TYPE_AM:
@ -205,14 +224,7 @@ void DemodulatorThread::threadMain() {
break;
}
amOutputCeil = 0;
for (int i = 0; i < bufSize; i++) {
ampmodem_demodulate(demodAM, inp->data[i], &demodOutputData[i]);
if (demodOutputData[i] > amOutputCeil) {
amOutputCeil = demodOutputData[i];
}
}
amOutputCeilMA = amOutputCeilMA + (amOutputCeil - amOutputCeilMA) * 0.05;
amOutputCeilMAA = amOutputCeilMAA + (amOutputCeilMA - amOutputCeilMAA) * 0.05;