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stereo demodulation preparations df8oe#3
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@DD4WH
DD4WH committed Oct 19, 2017
1 parent 40ca383 commit b0cec76
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Showing 4 changed files with 66 additions and 24 deletions.
75 changes: 54 additions & 21 deletions mchf-eclipse/drivers/audio/audio_driver.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3116,7 +3116,7 @@ static void AudioDriver_RxHandleIqCorrection(const uint16_t blockSize)

else // Automatic IQ imbalance correction
{ // Moseley, N.A. & C.H. Slump (2006): A low-complexity feed-forward I/Q imbalance compensation algorithm.
// in 17th Annual Workshop on Circuits, Nov. 2006, pp. 158�164.
// in 17th Annual Workshop on Circuits, Nov. 2006, pp. 158-164.
// http://doc.utwente.nl/66726/1/moseley.pdf
if (ts.twinpeaks_tested == 2)
{
Expand Down Expand Up @@ -3227,14 +3227,15 @@ static void AudioDriver_RxHandleIqCorrection(const uint16_t blockSize)
static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * const dst, const uint16_t blockSize)
{
const int16_t blockSizeDecim = blockSize/(int16_t)ads.decimation_rate;

// we copy volatile variables which are used multiple times to local consts to let the compiler to its optimization magic
// since we are in an interrupt, no one will change these anyway
// shaved off a few bytes of code
const uint8_t dmod_mode = ts.dmod_mode;
const uint8_t tx_audio_source = ts.tx_audio_source;
const uint8_t iq_freq_mode = ts.iq_freq_mode;
const uint8_t dsp_active = ts.dsp_active;
// const bool use_stereo = USE_TWO_CHANNEL_AUDIO && (dmod_mode == DEMOD_IQ || dmod_mode == DEMOD_SSBSTEREO || dmod_mode != DEMOD_SAMSTEREO);
const bool use_stereo = (dmod_mode == DEMOD_IQ || dmod_mode == DEMOD_SSBSTEREO || dmod_mode == DEMOD_SAMSTEREO);

float post_agc_gain_scaling;

Expand Down Expand Up @@ -3349,7 +3350,7 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
if (dvmode_signal == false)
{
const bool use_decimatedIQ =
FilterPathInfo[ts.filter_path].FIR_I_coeff_file == i_rx_new_coeffs
FilterPathInfo[ts.filter_path].FIR_I_coeff_file == i_rx_new_coeffs // lower than 3k8 bandwidth
&& dmod_mode != DEMOD_FM
&& dmod_mode != DEMOD_SAM
&& dmod_mode != DEMOD_AM;
Expand Down Expand Up @@ -3421,10 +3422,11 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
arm_add_f32(adb.i_buffer, adb.q_buffer, adb.a_buffer, blockSizeIQ); // sum of I and Q - USB
}
break;
case DEMOD_IQ: // leave I & Q as they are!
// for now, this is in fact SSB_STEREO = LSB-left, USB-right
case DEMOD_SSBSTEREO: // LSB-left, USB-right
case DEMOD_IQ: // leave I & Q as they are!

arm_add_f32(adb.i_buffer, adb.q_buffer, adb.a_buffer, blockSizeIQ); // sum of I and Q - USB
arm_sub_f32(adb.i_buffer, adb.q_buffer, adb.b_buffer, blockSizeIQ); // difference of I and Q - LSB
arm_sub_f32(adb.i_buffer, adb.q_buffer, adb.r_buffer, blockSizeIQ); // difference of I and Q - LSB
break;
case DEMOD_USB:
default:
Expand All @@ -3443,6 +3445,10 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
{
// TODO HILBERT
arm_fir_decimate_f32(&DECIMATE_RX, adb.a_buffer, adb.a_buffer, blockSize); // LPF built into decimation (Yes, you can decimate-in-place!)
if(use_stereo)
{
arm_fir_decimate_f32(&DECIMATE_RX, adb.r_buffer, adb.r_buffer, blockSize); // LPF built into decimation (Yes, you can decimate-in-place!)
}
}
/////////////////////////////////////////////

Expand All @@ -3466,16 +3472,29 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
if ((IIR_PreFilter.numStages > 0)) // yes, we want an audio IIR filter
{
arm_iir_lattice_f32(&IIR_PreFilter, adb.a_buffer, adb.a_buffer, blockSizeDecim);
if(use_stereo)
{
arm_iir_lattice_f32(&IIR_PreFilter, adb.r_buffer, adb.r_buffer, blockSizeDecim);
}

}

// now process the samples and perform the receiver AGC function
if(ts.agc_wdsp)
{
AudioDriver_RxAgcWdsp(blockSizeDecim, adb.a_buffer);
if(use_stereo)
{
AudioDriver_RxAgcWdsp(blockSizeDecim, adb.r_buffer);
}
}
else
{
AudioDriver_RxAgcProcessor(blockSizeDecim, adb.a_buffer);
if(use_stereo)
{
AudioDriver_RxAgcProcessor(blockSizeDecim, adb.r_buffer);
}
}

// DSP noise reduction using LMS (Least Mean Squared) algorithm
Expand Down Expand Up @@ -3587,9 +3606,16 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
}
}
arm_scale_f32(adb.a_buffer,scale_gain, adb.a_buffer, blockSizeDecim); // apply fixed amount of audio gain scaling to make the audio levels correct along with AGC

if(use_stereo)
{
arm_scale_f32(adb.r_buffer,scale_gain, adb.r_buffer, blockSizeDecim); // apply fixed amount of audio gain scaling to make the audio levels correct along with AGC
}
// this is the biquad filter, a notch, peak, and lowshelf filter
arm_biquad_cascade_df1_f32 (&IIR_biquad_1, adb.a_buffer,adb.a_buffer, blockSizeDecim);
if(use_stereo)
{
arm_biquad_cascade_df1_f32 (&IIR_biquad_1, adb.r_buffer,adb.r_buffer, blockSizeDecim);
}

#ifdef USE_RTTY_PROCESSOR
if (is_demod_rtty() && blockSizeDecim == 8) // only works when decimation rate is 4 --> sample rate == 12ksps
Expand All @@ -3613,12 +3639,20 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
if (INTERPOLATE_RX.phaseLength > 0)
{
arm_fir_interpolate_f32(&INTERPOLATE_RX, adb.a_buffer, adb.b_buffer, blockSizeDecim);
if(use_stereo)
{
arm_fir_interpolate_f32(&INTERPOLATE_RX, adb.r_buffer, adb.a_buffer, blockSizeDecim);
}
}
// additional antialias filter for specific bandwidths
// IIR ARMA-type lattice filter
if (IIR_AntiAlias.numStages > 0) // yes, we want an interpolation IIR filter
{
arm_iir_lattice_f32(&IIR_AntiAlias, adb.b_buffer, adb.b_buffer, blockSize);
if(use_stereo)
{
arm_iir_lattice_f32(&IIR_AntiAlias, adb.a_buffer, adb.a_buffer, blockSize);
}
}

} // end NOT in FM mode
Expand All @@ -3635,17 +3669,13 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
}

}
else if(dmod_mode == DEMOD_IQ)
{ // I & Q are raw data
if ((IIR_PreFilter.numStages > 0))
{
arm_iir_lattice_f32(&IIR_PreFilter, adb.q_buffer, adb.q_buffer, blockSize);
arm_iir_lattice_f32(&IIR_PreFilter, adb.i_buffer, adb.i_buffer, blockSize);
}
}

// this is the biquad filter, a highshelf filter
arm_biquad_cascade_df1_f32 (&IIR_biquad_2, adb.b_buffer,adb.b_buffer, blockSize);
if(use_stereo)
{
arm_biquad_cascade_df1_f32 (&IIR_biquad_2, adb.a_buffer,adb.a_buffer, blockSize);
}
}
}

Expand All @@ -3669,7 +3699,8 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c
}
else
{
arm_scale_f32(adb.b_buffer, LINE_OUT_SCALING_FACTOR, adb.a_buffer, blockSize); // Do fixed scaling of audio for LINE OUT and copy to "a" buffer in one operation
// arm_scale_f32(adb.b_buffer, LINE_OUT_SCALING_FACTOR, adb.a_buffer, blockSize); // Do fixed scaling of audio for LINE OUT and copy to "a" buffer in one operation
arm_scale_f32(adb.b_buffer, LINE_OUT_SCALING_FACTOR, adb.r_buffer, blockSize); // Do fixed scaling of audio for LINE OUT and copy to "a" buffer in one operation
//
// AF gain in "ts.audio_gain-active"
// 0 - 16: via codec command
Expand Down Expand Up @@ -3712,25 +3743,27 @@ static void AudioDriver_RxProcessor(AudioSample_t * const src, AudioSample_t * c

#ifdef USE_TWO_CHANNEL_AUDIO
// Stereo modes should be implemented here
if(ts.dmod_mode == DEMOD_IQ)
if(use_stereo)
{
dst[i].r = adb.i_buffer[i];
dst[i].l = adb.q_buffer[i];
dst[i].r = adb.a_buffer[i];
dst[i].l = adb.b_buffer[i];
}
else
{ // MONO
dst[i].r = dst[i].l = adb.b_buffer[i];
}
#else
dst[i].l = adb.b_buffer[i]; // VARIABLE LEVEL FOR SPEAKER
dst[i].r = adb.a_buffer[i]; // LINE OUT (constant level)
// dst[i].r = adb.a_buffer[i]; // LINE OUT (constant level)
dst[i].r = adb.r_buffer[i]; // LINE OUT (constant level)
#endif

}
// Unless this is DIGITAL I/Q Mode, we sent processed audio
if (tx_audio_source != TX_AUDIO_DIGIQ)
{
float32_t val = adb.a_buffer[i] * usb_audio_gain;
// float32_t val = adb.a_buffer[i] * usb_audio_gain;
float32_t val = adb.r_buffer[i] * usb_audio_gain;
audio_in_put_buffer(val);
audio_in_put_buffer(val);
}
Expand Down
2 changes: 2 additions & 0 deletions mchf-eclipse/drivers/audio/audio_driver.h
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Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,8 @@ typedef struct
float32_t a_buffer[IQ_BUFSZ];
float32_t b_buffer[IQ_BUFSZ];

float32_t r_buffer[IQ_BUFSZ]; // used for the right channel in STEREO DEMODULATION

float32_t agc_valbuf[BUFF_LEN]; // holder for "running" AGC value
float32_t DF;
float32_t pll_fmax;
Expand Down
6 changes: 6 additions & 0 deletions mchf-eclipse/drivers/ui/ui_driver.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1522,6 +1522,12 @@ void UiDriver_DisplayDemodMode()
case DEMOD_IQ:
txt = "IQ";
break;
case DEMOD_SSBSTEREO:
txt = "SSB-S";
break;
case DEMOD_SAMSTEREO:
txt = "SAM-S";
break;
default:
break;
}
Expand Down
7 changes: 4 additions & 3 deletions mchf-eclipse/hardware/uhsdr_board.h
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Original file line number Diff line number Diff line change
Expand Up @@ -212,9 +212,10 @@ struct mchf_waterfall
#define DEMOD_SAM 4
#define DEMOD_FM 5
#define DEMOD_DIGI 6
#define DEMOD_IQ 7
#define DEMOD_SSBSTEREO 8 // not yet used
#define DEMOD_MAX_MODE 7
#define DEMOD_SSBSTEREO 7
#define DEMOD_IQ 8 // not yet used
#define DEMOD_SAMSTEREO 9 // not yet used
#define DEMOD_MAX_MODE 6

// codec x demod
// analog USB LSB CW AM FM SAM
Expand Down

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