TIDUF16 December   2023

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Photodiode, TIA, and ADC
      2. 2.2.2 LED Driving
      3. 2.2.3 Power
      4. 2.2.4 Display, Orientation, and Communication Features
      5. 2.2.5 Software
        1. 2.2.5.1 Timing Structure
        2. 2.2.5.2 Oversampling and Digital Filtering to Increase Dynamic Range
        3. 2.2.5.3 Calculating Vitals
    3. 2.3 Highlighted Products
      1. 2.3.1 MSPM0L1306
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
      1. 3.2.1 TI GUI
      2. 3.2.2 CCS Project
      3. 3.2.3 Analog Engineers Calculator
    3. 3.3 Test Setup
    4. 3.4 Test Results
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks

2.2.5.2 Oversampling and Digital Filtering to Increase Dynamic Range

The key features of the TIDA-010267 reference design lay in the excellent dynamic range which can be achieved through oversampling and filtering digitally. The high-speed 12-bit ADC of the MSPM0L1306 can be oversampled as selected by the user, increasing the bit count to 16. This allows the design to take advantage of an increased ENOB, and therefore an increased dynamic range. To further increase the ENOB of the ADC signal, a moving average FIR filter of adjustable magnitude is used to filter out ambient noise in this design. These methods of increasing dynamic range are highly effective because of PPG signals operate at such low frequencies. A closer look of the effect of oversampling on dynamic range is demonstrated in Section 3.