Large Dynamic Range Amplifier Plus ADC
Total Page:16
File Type:pdf, Size:1020Kb
Large Dynamic Range Amplifier Plus ADC By Ted Hsueh Senior Project ELECTRICAL ENGINEERING DEPARTMENT California Polytechnic State University San Luis Obispo 2015 Abstract Nerve and muscle signal sampling proves difficult because of the large difference in magnitudes. Muscle signals loom a hundred or even a thousand times bigger and can hide the nerve signals. The Large Dynamic Range Amplifier plus Analog to Digital Converter (ADC) allows one device to retrieve both muscle and nerve signal information. The device has two parts: the ability to take high-resolution data from tenths of microvolts to several millivolts and filter out environmental noise, such as 60 Hz of electrical power lines or electro galvanic signals. This gives the ability to read muscle and nerve signals using one amplifier or device. TABLE OF CONTENTS ABSTRACT .................................................................................................................................................. 2 CHAPTER I: INTRODUCTION: .............................................................................................................. 5 CHAPTER II: CUSTOMER NEEDS, REQUIREMENTS, AND SPECIFICATIONS .......................... 5 CUSTOMER NEEDS ASSESSMENT ............................................................................................................................ 5 REQUIREMENTS AND SPECIFICATIONS .................................................................................................................. 5 CHAPTER III: FUNCTIONAL DECOMPOSITION ............................................................................... 7 LEVEL ZERO BLOCK DIAGRAM ................................................................................................................................ 7 LEVEL TWO BLOCK DIAGRAM.................................................................. ERROR! BOOKMARK NOT DEFINED. CHAPTER IV: DESIGN ........................................................................................................................... 10 DESIGN INPUT STAGE ............................................................................................................................................ 11 DESIGN NERVE SEPARATION ............................................................................................................................... 11 1. Low Pass and Subtraction ............................................................................................................................. 11 2. Low-Pass, All Pass, and Subtraction ......................................................................................................... 12 DESIGN MUSCLE SEPARATION ............................................................................................................................. 16 BOARD DESIGN AND SCHEMATIC ........................................................................................................................ 17 CHAPTER V: TEST RESULTS .............................................................................................................. 21 CHAPTER VI: ERRORS AND FIXES ................................................................................................... 26 APPENDIX A: REFERENCES ................................................................................................................ 29 APPENDIX B: BOARD BOM ................................................................................................................. 31 APPENDIX C. SENIOR PROJECT ANALYSIS .................................................................................... 37 SUMMARY OF FUNCTIONAL REQUIREMENTS .................................................................................................... 37 PRIMARY CONSTRAINTS........................................................................................................................................ 37 ECONOMICS ............................................................................................................................................................. 37 MANUFACTURING................................................................................................................................................... 40 ENVIRONMENTAL ................................................................................................................................................... 40 MANUFACTURABILITY ........................................................................................................................................... 40 SUSTAINABILITY ..................................................................................................................................................... 40 ETHICAL ................................................................................................................................................................... 40 HEALTH AND SAFETY ............................................................................................................................................ 40 SOCIAL AND POLITICAL ......................................................................................................................................... 41 DEVELOPMENT ....................................................................................................................................................... 41 TABLE OF FIGURES FIGURE 1: LEVEL ZERO BLOCK DIAGRAM ...................................................................................................................................... 7 FIGURE 2: LEVEL ONE BLOCK DIAGRAM ........................................................................................................................................ 8 FIGURE 3: BASIC DESIGN REQUIREMENT ..................................................................................................................................... 10 FIGURE 4: EXAMPLE INPUT SIGNAL .............................................................................................................................................. 10 FIGURE 5: BASIC OPERATION OF SEPARATING LARGE AMPLITUDE DIFFERENT SIGNALS ................................................... 11 FIGURE 6: EXAMPLE OF PHASE DELAY WHEN IMPLEMENTING DESIGN I ................................................................................ 12 FIGURE 7: DESIGN I TEST CIRCUIT ................................................................................................................................................ 12 FIGURE 8: ALL-PASS DESIGN I PHASE ........................................................................................................................................... 13 FIGURE 9: ALL-PASS DESIGN I CIRCUIT ........................................................................................................................................ 14 FIGURE 10: ALL-PASS DESIGN II CIRCUIT .................................................................................................................................... 14 FIGURE 11: NERVE SIGNAL CONDITIONING CIRCUIT ................................................................................................................. 15 FIGURE 12: FREQUENCY RESPONSE OF LOW PASS FILTER, 500HZ CUTOFF ......................................................................... 16 FIGURE 13: LOW PASS FILTER CIRCUIT DIAGRAM ..................................................................................................................... 16 FIGURE 14: BOARD LAYOUT ........................................................................................................................................................... 17 FIGURE 15: CHANNEL TWO OF THE INPUT STAGE AND NERVE SIGNAL SEPARATION (ACTUAL) ...................................... 17 FIGURE 16: NERVE SEPARATION ON THE BOARD LAYOUT. TWO CHANNELS ......................................................................... 18 FIGURE 17: NERVE SIGNAL CONDITIONING CIRCUIT (ACTUAL) ............................................................................................. 18 FIGURE 18: MUSCLE FILTERING AND CONDITIONING CIRCUIT (ACTUAL) ............................................................................. 19 FIGURE 19: MUSCLE FILTERING AND CONDITIONING BOARD LAYOUT .................................................................................. 19 FIGURE 20: ADS1198 ADC .......................................................................................................................................................... 20 FIGURE 21: BOARD LAYOUT OF ADC AND CONNECTORS .......................................................................................................... 20 FIGURE 22: BOARD LAYOUT FOR POWER .................................................................................................................................... 21 FIGURE 23: SETUP CONNECTIONS ................................................................................................................................................. 22 FIGURE 24: ACTUAL INPUT SIGNAL (2MVPP 1.5KHZ ON TOP OF 10MVPP 250HZ) ........................................................... 23 FIGURE 25: SCALED INPUT SIGNAL (20MVPP 1.5KHZ ON TOP OF 100MVPP 250HZ) ...................................................... 23 FIGURE 26: SIGNAL OUTPUT OF PREAMP.....................................................................................................................................