Laterizio
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mo/demodulatore ssb digitale
laterizio e' un modulatore e demodulatore per SSB a metodo weaver implementato su un DSP a basso consumo, per RTX radio portatili
In ricezione, i segnali complessi I e Q vengono campionati simultaneamente su due ADC con risoluzione di 10bit e frequenza di 20Khz, filtrati con un filtro FIR, e moltiplicati con un oscillatore numerico in quadratura. I due segnali vengono poi sommati o sottratti a seconda della banda laterale desiderata.
uC
http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en532298 dsPIC33FJ128GP802
- RAM: 16K
- Flash: 128K
- Timers: 5
- UART: 2
- primitive DSP
- ADC 10/12bit
- DAC 16bit
Mappa pin
| Pin | Funzione | Nome | porta sul uC |
|---|---|---|---|
| 1 | MCLR | MCLR | |
| 2 | Rx I in | AN0/VREF+/CN2/RA0 | |
| 3 | Rx Q in | AN1/VREF-/CN3/RA1 | |
| 4 | Dati ICSP | PGED1/AN2/C2IN-/RP0(1)/CN4/RB0 | |
| 5 | Clock ICSP | PGEC1/ AN3/C2IN+/RP1(1)/CN5/RB1 | |
| 6 | Tx Mic In | AN4/C1IN-/RP2/CN6/RB2 | |
| 7 | AN5/C1IN+/RP3/CN7/RB3 | ||
| 8 | V - | VSS | |
| 9 | Xtal 8MHz | OSC1/CLKI/CN30/RA2 | |
| 10 | Xtal 8MHz | OSC2/CLKO/CN29/PMA0/RA3 | |
| 11 | LSB/USB | SOSCI/RP4(1)/CN1/PMBE/RB4 | |
| 12 | BW Narrow/Wide | SOSCO/T1CK/CN0/PMA1/RA4 | |
| 13 | V + | VDD | |
| 14 | PGED3/ASDA1/RP5 /CN27/PMD7/RB5 | ||
| 15 | PGEC3/ASCL1/RP6(1)/CN24/PMD6/RB6 | ||
| 16 | INT0/RP7(1)/CN23/PMD5/RB7 | ||
| 17 | TCK/SCL1/RP8(1)/CN22/PMD4/RB8 | ||
| 18 | RSSI | TDO/SDA1/RP9(1)/CN21/PMD3/RB9 | |
| 19 | V - | VSS | |
| 20 | 10 uF tantalio verso VSS | VCAP | |
| 21 | Tx/Rx | PGED2/TDI/RP10(1)/CN16/PMD2/RB10 | |
| 22 | ? | PGEC2/TMS/RP11(1)/CN15/PMD1/RB11 | |
| 23 | Tx Q out + | AN12/DAC1RP/RP12(1)/CN14/PMD0/RB12 | |
| 24 | Q out - | AN11/DAC1RN/RP13(1)/CN13/PMRD/RB13 | |
| 25 | Tx I out + | AN10/DAC1LP/RTCC/RP14(1)/CN12/PMWR/RB14 | |
| 26 | Rx Audio out - | AN9/DAC1LN/RP15(1)/CN11/PMCS1/RB15 | |
| 27 | V - analogico | AVSS | |
| 28 | V + analogico | AVDD |
possibili alternative:
Letture
Phasing method:
- http://www.ece.umd.edu/~tretter/commlab/c6713slides/ch7.pdf
- http://www-inst.eecs.berkeley.edu/~ee120/fa99/notes/notes15.pdf
- http://www.katjaas.nl/hilbert/hilbert.html
- https://www.ece.uvic.ca/~elec350/lab_manual/data/SSB_theory.pdf
- http://www.dg5mk.de/pages/artikel/content-in-english-language/fft-ssb-modulation-and-demodulation---how-it-works.php
- http://tlfabian.blogspot.it/2013/01/implementing-hilbert-90-degree-shift.html
- http://rheslip.blogspot.it/2014/04/teensy-sdr-implementing-image.html
- https://it.mathworks.com/help/signal/examples/single-sideband-modulation-via-the-hilbert-transform.html
- http://www.moetronix.com/dspic/
- http://ae6ty.com/Papers_files/SDR-QrpQuarterly-Part-3.pdf
- http://forums.parallax.com/discussion/132977/hilbert-transform-prop-dsp
- http://www.dsprelated.com/showarticle/176.php
Weaver method: