title: Acoustic methods for obtaining the pressure reflection coefficient from a buffer rod based measurement cell.
abstract: The known acoustic methods for obtaining the pressure reflection coefficient from a buffer rod based measurement cell are presented, along with 2 new generic approaches for measuring the pressure reflection coefficient using 2 buffer rods enclosing the liquid to be characterized in a symmetrical arrangement. An acoustic transducer is connected to each of the buffer rods. The generic approaches are divided into a relative amplitude approach and a mixed amplitude approach. For the relative amplitude approach, families of 4, 5, or 6 echo signals can be used to obtain the pressure reflection coefficient. The mixed amplitude approach uses specific information about the transducers and/or the electronics sensitivities in receive mode to obtain the pressure reflection coefficient using families of 3, 4, 5, or 6 echo signals. Some of the new methods from the relative amplitude approach imply a reduced uncertainty relative to the previously known ABC method. The effect of the liquid attenuation, digitizer bit resolution, and the signal-to-noise ratio on the uncertainty characteristics of the pressure reflection coefficient are discussed, along with a discussion of the suitability of the various methods for different buffer materials.
authors.affiliation: 3-Phase Meas. AS, Bergen. erlend.bjorndal@3-phase.no
authors.forename: Erlend
authors.initials: E
authors.lastname: Bjørndal
authors.forename: Kjell-Eivind
authors.initials: KE
authors.lastname: Frøysa
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D000465:Algorithms; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008365:Manometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000295:instrumentation*; D014159:Transducers