MULTICORE, MULTITHREADED, PHASE-SYNCHRONOUS FM SOUND SYNTHESIZER by Justin Tomlin Senior Project ELECTRICAL ENGINEERING DEPARTMENT California Polytechnic State University San Luis Obispo 2011 1 Table of Contents List of Figures............................................................................................................................................ 3 Acknowledgements.................................................................................................................................... 4 Abstract...................................................................................................................................................... 5 Section 1 - Introduction..............................................................................................................................6 Project Overview/Motivation........................................................................................................... 6 Definition of Intended User.............................................................................................................. 6 Competitive Solutions...................................................................................................................... 6 Section 2 - Background..............................................................................................................................7 FM Synthesis.................................................................................................................................... 7 Common Parameter Modulation Schemes....................................................................................... 7 Section 3 - Requirements........................................................................................................................... 8 Functional Requirements.................................................................................................................. 8 Performance Specifications.............................................................................................................. 8 Section 4 - Design Approach Alternatives................................................................................................. 9 Oscillator...........................................................................................................................................9 Section 5 - Product Design.......................................................................................................................14 User Interface..................................................................................................................................14 Theory of Operation.................................................................................................................................15 Software Subsystems...................................................................................................................... 19 Software/Hardware Interfacing...................................................................................................... 22 Section 6 – Physical Construction and Integration.................................................................................. 23 Circuit Board Implementation........................................................................................................ 23 Enclosure Concept.......................................................................................................................... 23 Power Source.................................................................................................................................. 23 Section 7 – Integrated System Tests and Results..................................................................................... 25 Project (System-Level) Verification Testing...................................................................................25 Subsystem Verification Testing.......................................................................................................25 Summarized Test Results................................................................................................................31 Section 8 – Conclusions...........................................................................................................................32 Proposed Solutions to Design Shortcomings..................................................................................32 Further Improvements.................................................................................................................... 33 Section 9 – Bibliography..........................................................................................................................35 Appendix A: Parts List and Cost..............................................................................................................36 Budget.............................................................................................................................................36 Parts List:........................................................................................................................................ 36 Appendix B: Schedule.............................................................................................................................37 Appendix C: Program Listing.................................................................................................................. 39 Appendix D: Analysis of Senior Project Design.....................................................................................51 2 List of Figures Chapter 4 4.1: DPW Sawtooth Generation ........................................................................................ 9 4.2: tanh Square Generation............................................................................................... 10 4.3: tanh() function............................................................................................................. 10 4.4: Basic ModFM flowchart..............................................................................................11 4.5: Square to Triangle Conversion.................................................................................... 11 4.6: Phase-synchronous ModFM........................................................................................12 Chapter 5 5.1: Black Box Diagram..................................................................................................... 14 5.2: Photograph of Physical Interface.................................................................................15 5.3: Layout of Parameter Matrix........................................................................................ 15 5.4: Overall System Block Diagram...................................................................................16 5.5: Audio DAC Connection Diagram................................................................................17 5.6: ADC Connection Diagram...........................................................................................17 5.7: MIDI Interface Schematic........................................................................................... 18 5.8: Power Supply Schematic............................................................................................. 18 5.9: Software Subsystem Block Diagram...........................................................................19 5.10: I/O Port Map..............................................................................................................22 Chapter 6 6.1: Photograph of Board Implementation......................................................................... 23 6.2: Photograph of Panel Wiring........................................................................................ 24 Chapter 7 7.1: Power Supply/DAC Load Testing............................................................................... 25 7.2: AVDD Supply Noise....................................................................................................26 7.3: AVSS Supply Noise..................................................................................................... 26 7.4: Frequency Spectrum of 440 Hz Cosine Output...........................................................27 7.5: Frequency Spectrum (fo = 1760, k = 63, n = 7).......................................................... 28 7.6: Envelope Modulation of Amplitude (short and long attack/decay).............................28 7.7: Envelope Modulation of k (long attack, A440, n=2)...................................................29 7.8: LFO Modulation of Amplitude (short and long period).............................................. 29 7.9: LFO Modulation of k (long period, A440, n=2)..........................................................30 7.10: Plot for Determining Audio Latency......................................................................... 30 7.11: Performance Specification Test Results.................................................................... 31 3 Acknowledgements First of all, I would like to thank my senior project advisor Dr. Pilkington for his assistance in planning this project and addressing issues that came up along the way. The digital signal processing techniques and MATLAB exercises taught in his EE 419/459 lecture and lab were also invaluable in my research and design process. Secondly, I would like to thank Texas Instruments for fulfilling my multiple sample requests while