1 / 44

DSP for under £50

DSP for under £50. Ron Taylor G4GXO www.cumbriadesigns.co.uk. Signals to numbers – and back again. Microprocessor. Analogue. Digital. Analogue. Analogue to Digital Converter. Digital to Analogue Converter. Analogue to Digital Conversion. +ve. Voltage. 0V. -ve. Sampling points.

cain
Download Presentation

DSP for under £50

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DSP for under £50 Ron Taylor G4GXO www.cumbriadesigns.co.uk

  2. Signals to numbers – and back again Microprocessor Analogue Digital Analogue Analogue to Digital Converter Digital to Analogue Converter

  3. Analogue to Digital Conversion +ve Voltage 0V -ve Sampling points

  4. Analogue to Digital Conversion Amplitude of each sample above or below mid range is converted into a signed binary number +ve Number range 0 -ve 00010100 01110100 01110110 11100100 (sign bit sets –ve or +ve value) Each number sent serially from CODEC to processor

  5. Signals to numbers – and back again Microprocessor Analogue Digital Analogue Analogue to Digital Converter Digital to Analogue Converter

  6. The search for a suitable DSP development system • Low cost hardware • 16bits or more • Windows based supported development software (which should also be low cost or better still free!) • Capable of running a DSP IF scheme

  7. dsPIC30F processor Juha Niinikoski, OH2NLT “Cheap DSP”

  8. Juha Niinikoski, OH2NLT George Heron, N2APB “SDR Cube Transceiver” Direct Conversion Transceiver using a dsPIC33F processor

  9. A solution… • DSP only card with plenty of I/O for controls etc. • Microchip dsPIC33FJ64GP306 at 40MIPS (70MIPs with dsPIC33E)* (64 pin PTQF – not too difficult to solder) • Texas TLV320AIC23B stereo CODEC (28 pin SOP – easy to solder) • MPLAB IDE and the free version of the C30 compiler • Nominal 12V operation • I/O on 0.1” headers, optional pull up resistors, no analogue signal conditioning. *To be tested

  10. The Eden dsP Module

  11. I2C RS232 Eden dsP Module CODEC Config and control +12V SPI I/F PSU (Regs) L In R Stereo Audio in/out dsPIC33FJ64 TLV320AIC23 CODEC Bus for I2C Devices L Ext Comms Out R AC97 Codec I/F Serial Interfaces LEDs (2) I/O Ports Audio data transfer Indicators Controls (logic/switches etc)

  12. Eden dsP Module

  13. Eden dsP Module

  14. Eden dsP Module

  15. Eden dsP Module +12V PSU Programmer USB Connection Eden dsP Program is stored in the dsPIC33F flash memory MPLAB Development Software Programmer (MPLAB) Example programs Add the free C30 Compiler to edit the example Programs or start writing your own!

  16. Eden dsP Module Once programmed, the Eden dsP will run the software whenever it is power up – until it is overwritten with a new program. +12V Eden dsP Host equipment Receiver/Transceiver AF Filter Spectrum display etc., etc. The Eden dsP may be programmed whilst installed in its host equipment.

  17. What next?”

  18. FIR input output input output a x y Coeff Table b Digital Filters Two most common types IIR “Infinite Impulse Response” FIR “Finite Impulse Response”

  19. input output a x y b Digital Filters IIR - Infinite Impulse Response Filter • Feedback system, similar to analogue Op Amp Filter • Simple to code • Little memory used • Very fast execution • Roll off not spectacular • Phase varies with frequency • Potential for instability • Useful for general non critical filtering e.g, microphone filters etc

  20. FIR input output Coeff Table Digital Filters Common filter program FIR - Finite Impulse Response Filter • Based upon a delay line • Most commonly used filter type • Convolution process (multiply, add “MAC”) • Employs a table of constants to define filter • Capable of phenomenal performance • Fixed phase shift and delay • Memory and processor usage high Filter “Kernel” Sets filter parameters

  21. The FIR Filter 3 step “production line” process, similar to a conveyor belt in a factory… or a sushi bar?

  22. The FIR Filter • Load new sample into a delay line, shifting all current samples along one position.

  23. The FIR Filter • Load new sample into a delay line, shifting all current samples along one position. • Multiply each value on the delay line with a filter constant. ! a x b = c

  24. The FIR Filter • Load new sample into a delay line, shifting all current samples along one position. • Multiply each value on the delay line with a filter constant. • Add all of the multiplication results together to make the output sample.

  25. Input Delay Line (filter taps) Tap 1 Tap 7 a b c d e f g x x x x x x x Sum Step 2. Multiplication of each tap value by by a kernel constants (a, b, c, etc) Step 3. Accumulate (running sum of multiplications) Output One sample in, one sample out FIR Filter Step 1. Values move along delay line with each new sample Last Value Discarded (overwritten)

  26. FIR Code Written in assembler for fast (efficient) execution ;********************************************************************************************* ; ; FIR Filter ; ; Universal FIR Filter code ; ;********************************************************************************************* mov AF_in, w0 ; Get input and load into w0 mov #_fir_delay,w8 ; Load delay line start address into w8 mov w8, XMODSRT ; XMODSRT = start address of delay line mov _fir_delay_end, w8 ; Load delay line end address mov w8, XMODEND ; XMODEND = end address of delay line mov _fir_n, w1 ; Load number of taps (N) into w1 dec w1, w1 ; Decrement w1 = M (N-1) mov _fir_delay_ptr, w8 ; Load delay line pointer into w8 mov w0, [w8++] ; Move new sample into position pointed to by w8 mov w8, _fir_delay_ptr ; Update delay line pointer mov _fir_coef_end, w10 ; tap vector end to w10 clr A, [w8]+=2, w5, [w10]-+2, w6 ; Clear MAC Accumulator A, load w5 with sample pointed to by w8 and w6 ; with that at w10, post increment and decrement pointers repeat w1 ; Repeat MAC instruction w1 times = Number of taps - 1 mac w5*w6, A, [w8]+=2, w5, [w10]-=2, w6 sac.r a,w0 ; Round off result mov w0, _AF_out ; Copy output word to filter output ;********************************************************************************************* Load input sample Prepare delay line Set up addresses For delay line and Kernel table Multiply and add each record Output result

  27. FIR Filter Kernel // FIR Filter Kernel // // Ron Taylor Cumbria Designs 2012 // // Filter Kernel 1 N=201 Fs=8000 F1=500 F2=900 #define N 201 // Set number of taps const int fir_4_data[N]={ // Tap data 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0001, 0x0001, 0x0002, 0x0002, 0x0001, 0xFFFF, 0xFFFD, 0xFFFC, 0xFFFD, 0xFFFE, 0x0000, 0x0001, 0x0001, 0x0000, 0xFFFE, 0xFFFE, 0x0001, 0x0006, 0x000C, 0x0010, 0x000F, 0x0007, 0xFFFA, 0xFFEB, 0xFFE0, 0xFFDF, 0xFFE9, 0xFFFB, 0x000D, 0x0018, 0x0019, 0x0010, 0x0005, 0x0000, 0x0006, 0x0016, 0x0028, 0x002D, 0x001B, 0xFFF2, 0xFFBD, 0xFF90, 0xFF81, 0xFF9C, 0xFFDD, 0x0030, 0x0075, 0x0093, 0x0080, 0x0048, 0x0008, 0xFFDF, 0xFFDF, 0x0000, 0x0026, 0x002A, 0xFFF5, 0xFF8C, 0xFF16, 0xFED1, 0xFEF0, 0xFF83, 0x0068, 0x0153, 0x01E8, 0x01E8, 0x014B, 0x004D, 0xFF51, 0xFEBA, 0xFEB6, 0xFF2A, 0xFFBC, 0x0000, 0xFFB3, 0xFEE8, 0xFE12, 0xFDD1, 0xFEA9, 0x00AE, 0x0363, 0x05CB, 0x06C6, 0x0588, 0x0205, 0xFD15, 0xF845, 0xF54E, 0xF576, 0xF902, 0xFF09, 0x05B5, 0x0ADD, 0x0CCD, 0x0ADD, 0x05B5, 0xFF09, 0xF902, 0xF576, 0xF54E, 0xF845, 0xFD15, 0x0205, 0x0588, 0x06C6, 0x05CB, 0x0363, 0x00AE, 0xFEA9, 0xFDD1, 0xFE12, 0xFEE8, 0xFFB3, 0x0000, 0xFFBC, 0xFF2A, 0xFEB6, 0xFEBA, 0xFF51, 0x004D, 0x014B, 0x01E8, 0x01E8, 0x0153, 0x0068, 0xFF83, 0xFEF0, 0xFED1, 0xFF16, 0xFF8C, 0xFFF5, 0x002A, 0x0026, 0x0000, 0xFFDF, 0xFFDF, 0x0008, 0x0048, 0x0080, 0x0093, 0x0075, 0x0030, 0xFFDD, 0xFF9C, 0xFF81, 0xFF90, 0xFFBD, 0xFFF2, 0x001B, 0x002D, 0x0028, 0x0016, 0x0006, 0x0000, 0x0005, 0x0010, 0x0019, 0x0018, 0x000D, 0xFFFB, 0xFFE9, 0xFFDF, 0xFFE0, 0xFFEB, 0xFFFA, 0x0007, 0x000F, 0x0010, 0x000C, 0x0006, 0x0001, 0xFFFE, 0xFFFE, 0x0000, 0x0001, 0x0001, 0x0000, 0xFFFE, 0xFFFD, 0xFFFC, 0xFFFD, 0xFFFF, 0x0001, 0x0002, 0x0002, 0x0001, 0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, };

  28. FIR DesignerA free FIR design program fromthose really nice people at;www.cumbriadesigns.co.uk

  29. Demonstration Designing a high performance audio CW Filter • FIR Filter • 300Hz Bandwidth centred on 700Hz • Design and test filter in “FIR Designer” • Demonstrate filter using an FT817 • AF input from headphone socket • External LM380 AF power amplifier

  30. ; Filter Kernel N=301 Fs=8000 F1=550 F2=850 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0xFFFF, 0xFFFF, 0x0000, 0x0001, 0x0002, 0x0003, 0x0003, 0x0003, 0x0000, 0xFFFD, 0xFFFB, 0xFFF9, 0xFFFA, 0xFFFC, 0x0001, 0x0005, 0x0008, 0x0008, 0x0006, 0x0002, 0xFFFE, 0xFFFC, 0xFFFC, 0xFFFE, 0x0000, 0x0000, 0xFFFE, 0xFFFB, 0xFFF7, 0xFFF5, 0xFFF8, 0x0000, 0x000C, 0x0017, 0x001D, 0x001A, 0x000D, 0xFFFA, 0xFFE6, 0xFFD9, 0xFFD7, 0xFFE2, 0xFFF6, 0x000D, 0x001E, 0x0024, 0x001F, 0x0011, 0x0002, 0xFFF9, 0xFFF9, 0x0000, 0x0008, 0x0009, 0xFFFE, 0xFFE8, 0xFFCF, 0xFFC1, 0xFFC6, 0xFFE5, 0x0017, 0x004D, 0x0073, 0x0078, 0x0056, 0x0016, 0xFFCA, 0xFF8C, 0xFF72, 0xFF84, 0xFFBA, 0x0000, 0x003C, 0x0059, 0x0053, 0x0034, 0x0010, 0xFFFD, 0x0006, 0x0024, 0x0043, 0x0047, 0x001F, 0xFFCC, 0xFF67, 0xFF19, 0xFF0B, 0xFF52, 0xFFE7, 0x009F, 0x013D, 0x0185, 0x0157, 0x00BA, 0xFFE0, 0xFF10, 0xFE92, 0xFE8B, 0xFEF4, 0xFF9E, 0x0040, 0x00A0, 0x00A3, 0x0060, 0x0011, 0xFFF7, 0x0038, 0x00C4, 0x0158, 0x0194, 0x0129, 0x0000, 0xFE5A, 0xFCC2, 0xFBE1, 0xFC42, 0xFE0B, 0x00E0, 0x03F2, 0x0637, 0x06C9, 0x053A, 0x01D1, 0xFD7C, 0xF98F, 0xF758, 0xF7AC, 0xFA94, 0xFF43, 0x0451, 0x082A, 0x099A, 0x082A, 0x0451, 0xFF43, 0xFA94, 0xF7AC, 0xF758, 0xF98F, 0xFD7C, 0x01D1, 0x053A, 0x06C9, 0x0637, 0x03F2, 0x00E0, 0xFE0B, 0xFC42, 0xFBE1, 0xFCC2, 0xFE5A, 0x0000, 0x0129, 0x0194, 0x0158, 0x00C4, 0x0038, 0xFFF7, 0x0011, 0x0060, 0x00A3, 0x00A0, 0x0040, 0xFF9E, 0xFEF4, 0xFE8B, 0xFE92, 0xFF10, 0xFFE0, 0x00BA, 0x0157, 0x0185, 0x013D, 0x009F, 0xFFE7, 0xFF52, 0xFF0B, 0xFF19, 0xFF67, 0xFFCC, 0x001F, 0x0047, 0x0043, 0x0024, 0x0006, 0xFFFD, 0x0010, 0x0034, 0x0053, 0x0059, 0x003C, 0x0000, 0xFFBA, 0xFF84, 0xFF72, 0xFF8C, 0xFFCA, 0x0016, 0x0056, 0x0078, 0x0073, 0x004D, 0x0017, 0xFFE5, 0xFFC6, 0xFFC1, 0xFFCF, 0xFFE8, 0xFFFE, 0x0009, 0x0008, 0x0000, 0xFFF9, 0xFFF9, 0x0002, 0x0011, 0x001F, 0x0024, 0x001E, 0x000D, 0xFFF6, 0xFFE2, 0xFFD7, 0xFFD9, 0xFFE6, 0xFFFA, 0x000D, 0x001A, 0x001D, 0x0017, 0x000C, 0x0000, 0xFFF8, 0xFFF5, 0xFFF7, 0xFFFB, 0xFFFE, 0x0000, 0x0000, 0xFFFE, 0xFFFC, 0xFFFC, 0xFFFE, 0x0002, 0x0006, 0x0008, 0x0008, 0x0005, 0x0001, 0xFFFC, 0xFFFA, 0xFFF9, 0xFFFB, 0xFFFD, 0x0000, 0x0003, 0x0003, 0x0003, 0x0002, 0x0001, 0x0000, 0xFFFF, 0xFFFF, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

  31. Information header added and data formatted for use with C program // FIR Filter Kernel // // Ron Taylor Cumbria Designs 2012 // // Filter Kernel N=301 Fs=8000 F1=550 F2=850 #define N 301 // Set number of taps const int fir_coeff[N]={ // Tap data 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0xFFFF, 0xFFFF, 0x0000, 0x0001, 0x0002, 0x0003, 0x0003, 0x0003, 0x0000, 0xFFFD, 0xFFFB, 0xFFF9, 0xFFFA, 0xFFFC, 0x0001, 0x0005, 0x0008, 0x0008, 0x0006, 0x0002, 0xFFFE, 0xFFFC, 0xFFFC, 0xFFFE, 0x0000, 0x0000, 0xFFFE, 0xFFFB, 0xFFF7, 0xFFF5, 0xFFF8, 0x0000, 0x000C, 0x0017, 0x001D, 0x001A, 0x000D, 0xFFFA, 0xFFE6, 0xFFD9, 0xFFD7, 0xFFE2, 0xFFF6, 0x000D, 0x001E, 0x0024, 0x001F, 0x0011, 0x0002, 0xFFF9, 0xFFF9, 0x0000, 0x0008, 0x0009, 0xFFFE, 0xFFE8, 0xFFCF, 0xFFC1, 0xFFC6, 0xFFE5, 0x0017, 0x004D, 0x0073, 0x0078, 0x0056, 0x0016, 0xFFCA, 0xFF8C, 0xFF72, 0xFF84, 0xFFBA, 0x0000, 0x003C, 0x0059, 0x0053, 0x0034, 0x0010, 0xFFFD, 0x0006, 0x0024, 0x0043, 0x0047, 0x001F, 0xFFCC, 0xFF67, 0xFF19, 0xFF0B, 0xFF52, 0xFFE7, 0x009F, 0x013D, 0x0185, 0x0157, 0x00BA, 0xFFE0, 0xFF10, 0xFE92, 0xFE8B, 0xFEF4, 0xFF9E, 0x0040, 0x00A0, 0x00A3, 0x0060, 0x0011, 0xFFF7, 0x0038, 0x00C4, 0x0158, 0x0194, 0x0129, 0x0000, 0xFE5A, 0xFCC2, 0xFBE1, 0xFC42, 0xFE0B, 0x00E0, 0x03F2, 0x0637, 0x06C9, 0x053A, 0x01D1, 0xFD7C, 0xF98F, 0xF758, 0xF7AC, 0xFA94, 0xFF43, 0x0451, 0x082A, 0x099A, 0x082A, 0x0451, 0xFF43, 0xFA94, 0xF7AC, 0xF758, 0xF98F, 0xFD7C, 0x01D1, 0x053A, 0x06C9, 0x0637, 0x03F2, 0x00E0, 0xFE0B, 0xFC42, 0xFBE1, 0xFCC2, 0xFE5A, 0x0000, 0x0129, 0x0194, 0x0158, 0x00C4, 0x0038, 0xFFF7, 0x0011, 0x0060, 0x00A3, 0x00A0, 0x0040, 0xFF9E, 0xFEF4, 0xFE8B, 0xFE92, 0xFF10, 0xFFE0, 0x00BA, 0x0157, 0x0185, 0x013D, 0x009F, 0xFFE7, 0xFF52, 0xFF0B, 0xFF19, 0xFF67, 0xFFCC, 0x001F, 0x0047, 0x0043, 0x0024, 0x0006, 0xFFFD, 0x0010, 0x0034, 0x0053, 0x0059, 0x003C, 0x0000, 0xFFBA, 0xFF84, 0xFF72, 0xFF8C, 0xFFCA, 0x0016, 0x0056, 0x0078, 0x0073, 0x004D, 0x0017, 0xFFE5, 0xFFC6, 0xFFC1, 0xFFCF, 0xFFE8, 0xFFFE, 0x0009, 0x0008, 0x0000, 0xFFF9, 0xFFF9, 0x0002, 0x0011, 0x001F, 0x0024, 0x001E, 0x000D, 0xFFF6, 0xFFE2, 0xFFD7, 0xFFD9, 0xFFE6, 0xFFFA, 0x000D, 0x001A, 0x001D, 0x0017, 0x000C, 0x0000, 0xFFF8, 0xFFF5, 0xFFF7, 0xFFFB, 0xFFFE, 0x0000, 0x0000, 0xFFFE, 0xFFFC, 0xFFFC, 0xFFFE, 0x0002, 0x0006, 0x0008, 0x0008, 0x0005, 0x0001, 0xFFFC, 0xFFFA, 0xFFF9, 0xFFFB, 0xFFFD, 0x0000, 0x0003, 0x0003, 0x0003, 0x0002, 0x0001, 0x0000, 0xFFFF, 0xFFFF, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, };

  32. Headphone Socket AF Amplifier DSP Module Speaker AF Out AF In Demonstration

  33. Headphone Socket AF Amplifier Speaker AF Out AF In Demonstration Signal path control Eden dsP card

  34. DSP in Radio

  35. DSP in Radio Two general architectures; DSP IF System Direct Conversion

  36. Filter Bank Demod DDS Digital phase shifter PC or DSP Unit AF Amplifier Speaker DSP Receiver Architecture Direct Conversion Receiver AF Out High IP3 switching Mixers FST3125 etc

  37. DSP Receiver Architecture DSP IF Dual Conversion, VLF 2nd IF Crystal Filter 6kHz 2nd IF 15kHz Preselector 2nd Mixer IF Amplifier 15kHz IF Out 1st IF 20MHz Carrier oscillator VFO 15kHz IF In AF Amplifier DSP Module (2nd IF) AF Out Speaker

  38. AGC DSP Receiver Architecture Multirate DSP IF 48kHz Sampling Rate 9.6Hz Sampling Rate AF I Channel DSP Module 3kHz Phase shifting filters Decimator 15kHz IF input to mixers 5 Sin 15kHz IF In Demod AF Out 15kHz quad CIO Cos Gain control Auto-notch De-noiser 5 Decimator 3kHz AF Q Channel

  39. ;******************************************************************************************;****************************************************************************************** ; ; I and Q Mixers ; ; ;****************************************************************************************** mixers: ; I mixer mov _I_mix_in, w1 ; Get input signal and place in w1 mov _I_carrier,w0 ; Get carrier and place in w0 mul.ss w0, w1, w2 ; Signed 16bit x 16bit multiply, 32 bit result in w2 and w3 mov w3, _I_mix_out ; Save most significant word to mixer output ; Q mixer mov _Q_mix_in, w1 ; Get input signal and place in w1 mov _Q_carrier,w0 ; Get carrier and place in w0 mul.ss w0, w1, w2 ; Signed 16bit x 16bit multiply, 32 bit result in w2 and w3 mov w3, _Q_mix_out ; Save most significant word to mixer output return

  40. AGC DSP IF Demo 48kHz Sampling Rate 9.6Hz Sampling Rate AF I Channel DSP Module 3kHz Phase shifting filters Decimator 15kHz IF input to mixers 5 Sin 15kHz IF In Demod AF Out 15kHz quad CIO Cos Gain control Auto-notch De-noiser 5 Decimator 3kHz AF Q Channel

  41. Getting Started in DSP • “Eden dsP” Card, about £50 to build • Software MPLAB, C30, FIR Designer, demo programs - all free! • PIC programmer (PICkit 3 etc) • Modest PC for programming • Literature • Digital Signal Processing, Steven Smith • Digital Signal Processing Technology (ARRL), Doug Smith • ARRL/RSGB Handbooks • Beginners Guide to C, Greg Perry • The C Programming Language, Brian Kernigham and Dennis Ritchie

More Related