SLAA889A March   2019  – July 2021 MSP430FR6041 , MSP430FR6043 , MSP430FR60431 , MSP430FR6045 , MSP430FR6047 , MSP430FR60471

 

  1.   Trademarks
  2. 1Flow Metering Background
    1. 1.1 Water Flow Velocity Estimation
      1. 1.1.1 Velocity of Ultrasound in Water is Known
      2. 1.1.2 Velocity of Ultrasound in Water is Unknown
  3. 2Algorithms for Ultrasonic Water Flow Metering
    1. 2.1 Correlation Based Technique for Differential TOF Estimation
    2. 2.2 Absolute Time-of-Flight (AbsTOF) Measurement (Tup and Tdn)
      1. 2.2.1 AbsTOF Calculation
        1. 2.2.1.1 Acquisition Algorithm for AbsTOF
        2. 2.2.1.2 Tracking Algorithm for AbsTOF
  4. 3References
  5. 4Revision History

2.2 Absolute Time-of-Flight (AbsTOF) Measurement (Tup and Tdn)

As given in Section 1.1.2, estimating an accurate absolute time of flight in water means that a temperature sensor is not needed to compute the velocity of sound in water. Given that the whole signal waveform is captured using an ADC, there are different algorithms that can be used to calculate the AbsTOF. The following section describes two algorithms, one that is implemented as part of the USS Software Library and one that is planned to be implemented as part of the future releases of the USS Software Library.