Project10 presentation
- 1. BPSK RF Receiver Team 10 Michael Russell Shawn Kuo Amit Patel
- 2. Objective Successfully demodulate BPSK data sent at RF from one DSP to another Demonstrate feasibility of programmable back-end receiver Develop future tool for DSP lab
- 3. End-user Benefits A quick and simple point-to-point digital communication solution Scalable module that is capable of handling multiple demodulation schemes without hardware redesign Capable of receiving over a large frequency range
- 4. Original Design Review Design Schematic BW ~ 10's of MHz's AD8343 AD605 f =44.1KHz Universal Eval PC Rx CS4226 DSP AR5000 AD605 fc = 10.7 MHz CODEC ECS-10.7-7.5B AD605 Teraterm PBP-10.7 BW ~ 200 KHz fc=10.7 MHz - 11.025 KHz DDS CPLD AD9854 LO Mach211SP Crystal 60 MHz
- 5. Software Implementation Differential BPSK Pi-Radian Ambiguity Symbol Quantization and Unmapping Phase-Locked Loop Carrier Recovery Coherent Detection Symbol Timing
- 6. Differential BPSK Symbol Mapping
- 9. Simulation Results Generated BPSK Waveform Received BPSK Waveform
- 10. RF Receive Stage 10.7 MHz BPF Fixed Gain Amp 0.528 MHz LPF Software Transmitted 8dB BPSK DSP 2 Attenuator 25 dB Function Generator 10.7 MHz LPF (Simulates Noise) Fixed Gain Amp 25d B 3dB Attenuator 21.4 MHz LPF DDS Local Oscillator DSP 1
- 11. RF Stage - Preselector Maching Network Monolithic Monolithic Maching Network Crystal Filter Crystal Filter Ta se F n t no Pe e c rd ) rn fr u cio f rs l t ( B eo P ae f rsl t h s o Pee c r eo 0 h g e r_3 ( ,1) 20 0 ...cin _N tok ..S2 ) c g ewr_3 ( ,1) ...t in _N tok ..S2 ) -0 1 10 0 -0 2 -0 3 w 0 -0 4 -0 10 -0 5 h -0 6 -0 20 1 .6 0 7 1 .6 0 8 1 .6 0 9 1 .7 0 0 1 .7 0 1 1 .7 0 2 1 .7 0 3 1 .6 07 1 .6 08 1 .6 09 1 .7 00 1 .7 01 1 .7 02 1 .7 03 f qM z r , H e f qM z r , H e
- 12. Preselector Matching Network Input Impedance 30 50 m1 Matching Network 30 00 m1 fq 0 0 H r =1 .7 M z e Rn 7 7 5 i =2 5 .7 6 20 50 R 20 00 in C L R R2 10 50 C1 L2 R=5 Oh 0 m C=4 p L .8 u 0 F =5 5 H 10 00 R= 50 0 0 10 50 10 00 50 0 m 2 Zin = 2580 - j 1040 ` Xn i 0 fq 0 0 H r =1 .7 M z e X =- 0 3 4 in 1 3 .4 8 - 0 50 m2 - 00 10 - 50 10 - 00 20 1 .0 0 1 .5 0 1 .0 1 1 .5 1 1 .0 2 fqM z r , H e
- 13. Measured Signals Transmitted signal Signal after preselector Signal after mixing (baseband) Unfiltered DDS signal (LO) Filtered DDS signal
- 15. Filtered Signal
- 16. Filtered Signal
- 17. Baseband Signal
- 20. Output Interface Write decoded characters to memory and serial port simultaneously Interact with serial port through Tera Term
- 21. Theoretical Probability of Error Q Constellation I Symbol B Symbol A Q Constellation w/Noise I Symbol B Symbol A
- 22. Theoretical Probability of Error Received Symbol: Mapping Q I Symbol B Symbol A Result: Q(sqrt(2*Energy/Noise)) or Q(sqrt(2*SNR))
- 23. Calculating SNR The SNR was calculated by measuring separately measuring the signal power and the noise power after the preselector filter. 10.7 MHz BPF Fixed Gain Amp Transmitted 8dB 25 dB BPSK Attenuator Function Noise Measured Here Generator (Simulates Noise)
- 24. Calculated Probability of Error Calculated Byte Error (upper bound) Took 125KB of data Accurate for large amounts of noise Good order of magnitude approximation for low noise
- 25. Error Results Error Calculations Theoretical Calculated Noise Level (p-p) Noise SNR (dB/dB) Noise SNR (W/W) Perror (%) Perror (%) 100 mV 26.60 457.000 5.00E-199 0.00 500 mV 11.32 13.550 1.00E-05 0.05 800 mV 7.20 5.025 0.60 0.18 1500 mV 1.74 1.490 4.22 1.30 3000 mV -4.30 0.372 19.50 6.80
- 26. Tolerance of PLL Variation in Frequency Drifting in DDS Temperature Result PLL Frequency Tolerance Noise Level (p-p) Upper Bound (Hz) Lower Bound (Hz) 100 mV 9 -32 500 mV 8 -32 800 mV 8 -32 1500 mV 8 -32 3000 mV 8 -31
- 27. Successes Demodulated BPSK data sent at RF from one DSP to another Demonstrated feasibility of programmable back-end receiver Breadboard design produced expected behavior
- 28. Challenges Transmitting BPSK signal at RF Used passive mixer and DDS Used coaxial channel instead of air Bandlimiting Signal Use of Narrow Bandwidth Crystal Filter Matching Network Working around Serial Port interrupts
- 29. Future Developments Rev1.1 Solve Serial Port Issues for live data Printed Circuit Board Add Faster A/D Implement more Demodulation Schemes
- 30. Questions???