kopia lustrzana https://github.com/kamocat/uSDX
Changed to single ISR for dual-channel I/Q ADC sampling with Hilbert transform in Q, and sample correction (linear interpolation) in I channel.
guido
rodzic
4ee592b947
commit
8f9bdfcbf0
115
QCX-SSB.ino
115
QCX-SSB.ino
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@ -2,7 +2,7 @@
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//
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// https://github.com/threeme3/QCX-SSB
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#define VERSION "1.01f"
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#define VERSION "1.01g"
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// QCX pin defintion
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#define LCD_D4 0
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@ -586,9 +586,7 @@ volatile bool cw_event = false;
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// This is the ADC ISR, issued with sample-rate via timer1 compb interrupt.
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void dsp_rx()
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{ // jitter dependent things first
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uint8_t low = ADCL; // ADC sample 10-bits analog input, first ADCL, then ADCH
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uint8_t high = ADCH;
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int16_t adc = ((high << 8) | low) - 512;
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int16_t adc = (ADCL | (ADCH << 8)) - 512; // ADC sample 10-bits analog input, NOTE: first ADCL, then ADCH
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static int16_t dc;
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dc += (adc - dc) / 2;
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@ -658,41 +656,81 @@ ISR(TIMER2_COMPB_vect) // Timer2 COMPB interrupt
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}
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#else
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#define IQ_MOD 1
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ISR(TIMER2_COMPB_vect) // Timer2 COMPB interrupt
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{
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#ifdef ADC_NR
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interrupts();
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sleep_cpu();
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noInterrupts();
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uint8_t low = ADCL; // ADC sample 10-bits analog input, first ADCL, then ADCH
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uint8_t high = ADCH;
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static int16_t i, q;
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#undef R // Decimating 2nd Order CIC filter
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#define R 4 //8 // Rate change from 62.5/2 kSPS to 7812.5SPS per chan, providing 12dB gain
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// process I for even samples
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if((numSamples % 2) == 0){ // at 62.5kSPS about 75% CPU load (excluding the Comb branch)
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#ifdef IQ_MOD
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ADMUX = 1 | (1 << REFS1) | (1 << REFS0); // prepare next Q conversion, 1v1 ref enabled
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#else
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uint8_t low = ADCL; // ADC sample 10-bits analog input, first ADCL, then ADCH
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uint8_t high = ADCH;
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ADCSRA |= (1 << ADSC); // start ADC conversion (triggers ADC interrupt)
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ADMUX = 2 | (1 << REFS0); // prepare next Q conversion (use dummy)
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#endif
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int16_t adc = ((high << 8) | low) - 512;
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ADCSRA |= (1 << ADSC); // start next ADC conversion (trigger ADC interrupt if ADIE flag is set)
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int16_t adc = (ADCL | (ADCH << 8)) - 512; // current ADC sample 10-bits analog input, NOTE: first ADCL, then ADCH
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static int16_t dc;
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dc += (adc - dc) / 2;
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int16_t ac = adc - dc; // DC decoupling
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// Correct I/Q sample delay by means of linear interpolation
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static int16_t prev_adc;
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int16_t corr_adc = (prev_adc + adc) / 2;
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prev_adc = adc;
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// Decimating 2nd Order CIC filter
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#define R 8 // Rate change from 62.5kSPS to 7812.5SPS, providing 18dB gain
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static int16_t zi1, zi2, zd1, zd2;
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zi2 = zi1 + zi2; // Integrator section
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zi1 = ac + zi1;
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if((numSamples % R) == 0){
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int16_t d1 = zi2 - zd1; // Comb section
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ac = d1 - zd2;
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zd2 = d1;
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zd1 = zi2;
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if(mode == CW) ac = filt_cwn(ac /* *64 */ * 4 );
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else ac = ac >> drive; //ac = agc(ac);
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ac=min(max(ac, -128), 127); // clip
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OCR1AL = ac + 128;
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static int16_t dc;
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dc += (corr_adc - dc) / 2;
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int16_t ac = corr_adc - dc; // DC decoupling
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static int16_t zi1, zi2, zd1, zd2;
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zi2 = zi1 + zi2; // Integrator section
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zi1 = ac + zi1;
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if((numSamples % (R*2)) == 0){ // I-Comb branch: about 7% CPU load
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int16_t d1 = zi2 - zd1; // Comb section
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static int16_t v[16];
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/* i = */ v[15] = d1 - zd2;
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zd2 = d1;
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zd1 = zi2;
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for(uint8_t j = 0; j != 15; j++) v[j] = v[j + 1];
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i = v[7]; // Delay to match Hilbert transform on Q branch
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// post processing I and Q results
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ac = i + q;
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if(mode == CW) ac = filt_cwn(ac /* *64 */ * 4 );
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else ac = ac >> drive; //ac = agc(ac);
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i=min(max(ac, -128), 127); // clip
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OCR1AL = ac + 128;
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}
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}
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// process Q for odd samples
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else {
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#ifdef IQ_MOD
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ADMUX = 0 | (1 << REFS1) | (1 << REFS0); // prepare next I conversion, 1v1 ref enabled
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#else
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ADMUX = 0 | (1 << REFS0); // prepare next I conversion
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#endif
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ADCSRA |= (1 << ADSC); // start next ADC conversion (trigger ADC interrupt if ADIE flag is set)
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int16_t adc = (ADCL | (ADCH << 8)) - 512; // current ADC sample 10-bits analog input, NOTE: first ADCL, then ADCH
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static int16_t dc;
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dc += (adc - dc) / 2;
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int16_t ac = adc - dc; // DC decoupling
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static int16_t zi1, zi2, zd1, zd2;
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zi2 = zi1 + zi2; // Integrator section
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zi1 = ac + zi1;
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if((numSamples % (R*2)) == ((R*2)-1) ){ // Q-Comb branch: about 17% CPU load - executed just 1 sample before executing I-Comb (and final) branch
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int16_t d1 = zi2 - zd1; // Comb section
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static int16_t v[16];
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/* q = */ v[15] = d1 - zd2;
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zd2 = d1;
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zd1 = zi2;
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for(uint8_t j = 0; j != 15; j++) v[j] = v[j + 1];
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q = ((v[0] - v[14]) * 2 + (v[2] - v[12]) * 8 + (v[4] - v[10]) * 21 + (v[6] - v[8]) * 15) / 128 + (v[6] - v[8]) / 2; // Hilbert transform, 40dB side-band rejection in 400..1900Hz (@4kSPS) when used in image-rejection scenario; (Hilbert transform require 5 additional bits)
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}
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}
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numSamples++;
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}
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@ -776,9 +814,9 @@ void adc_stop()
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ADMUX |= (1 << REFS0); // restore reference voltage AREF (5V)
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}
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static uint8_t bandval = 2; //4
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#define N_BANDS 7 //13
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uint32_t band[] = { 3573000, 5357000, 7074000, 10136000, 14074000, 18100000, 21074000 }; //{ 472000, 1840000, 3573000, 5357000, 7074000, 10136000, 14074000, 18100000, 21074000, 24915000, 28074000, 50313000, 70101000 };
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static uint8_t bandval = 4; //2
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#define N_BANDS 14 //7
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uint32_t band[] = { 472000, 1840000, 3573000, 5357000, 7074000, 10136000, 14074000, 18100000, 21074000, 24915000, 28074000, 50313000, 70101000, 144125000 }; // { 3573000, 5357000, 7074000, 10136000, 14074000, 18100000, 21074000 };
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enum step_t { STEP_10M, STEP_1M, STEP_500k, STEP_100k, STEP_10k, STEP_1k, STEP_500, STEP_100, STEP_10, STEP_1 };
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volatile int8_t stepsize = STEP_1k;
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@ -799,7 +837,7 @@ void encoder_vect(int8_t sign)
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}
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if(stepval < STEP_100) freq %= 1000; // when tuned and stepsize > 100Hz then forget fine-tuning details
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freq += sign * stepval;
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freq = max(1, min(99999999, freq));
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//freq = max(1, min(99999999, freq));
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change = true;
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}
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@ -1112,12 +1150,13 @@ float getTemp()
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return (float)WDTmicrosTime * 0.0026 - 3668.1; //calibrate here
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}
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*/
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//#define SAFE 1
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#define SAFE 1
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void setup()
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{
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#ifdef SAFE
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// Benchmark ADC_vect() ISR (this needs to be done in beginning of setup() otherwise when VERSION containts 5 chars, mis-alignment impact performance by a few percent)
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numSamples = 0;
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uint32_t t0, t1;
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t0 = micros();
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TIMER2_COMPB_vect();
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@ -1,5 +1,5 @@
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# **ⓆⒸⓍ-ⓈⓈⒷ**
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# QCX-SSB: SSB with your QCX transceiver (modification)
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This is a simple and experimental modification that transforms a [QCX] into a (Class-E driven) SSB transceiver. It can be used to make QRP SSB contacts, or (in combination with a PC) used for the digital modes such as FT8. It can be fully-continuous tuned through bands 160m-10m in the LSB/USB-modes with a 2400Hz bandwidth has up to 5W PEP SSB output and features a software-based full Break-In VOX for fast RX/TX switching in voice and digital operations.
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