SLAAE25 May   2021 MSP430FR2355 , MSP430FR2355

 

  1.   Trademarks
  2. 1Introduction
  3. 2Theory of Operation
  4. 3Single-Chip Design
  5. 4Hardware
  6. 5Software
    1. 5.1 Sample and Condition the PIN Diode Signal
    2. 5.2 Sample and Measurement Sequence
    3. 5.3 First Stage DC Tracking
    4. 5.4 Low-Pass FIR Filter
    5. 5.5 Calculate Heart and SpO2
  7. 6Debug GUI
  8. 7Test Result
  9. 8Summary
  10. 9References

5.4 Low-Pass FIR Filter

In order to increase the SNR of the ADC signal, the FIR filtering is used to filter out the 50Hz ambient noise in this solution. As shown in Figure 5-5, the data after FIR filtering is smoother. And FR2355 integrates a hardware multiplier (MPY32) module, which can speed up FIR filtering.

GUID-84C49911-3824-4D87-8FB7-FA7947192668-low.png Figure 5-5 Low-Pass FIR Filter