NEMA UD 2-2004 (R2009)

Foreword to Revision Three
Foreword to May 1998 Edition
Foreword to Revision One
Foreword to 1992 Version
Purpose
Scope
Road Map
Section 1 DEFINITIONS
Section 2 REFERENCED DOCUMENTS
Section 3 MEASUREMENT DEVICE CHARACTERISTICS
  3.1 Introduction
  3.2 Scope
  3.3 Hydrophone Characteristics
      3.3.1 Hydrophone Sensitivity
      3.3.2 Hydrophone System Frequency Response
      3.3.3 Effective Hydrophone Diameter
      3.3.4 Dynamic Range and Linearity
      3.3.5 Field Measurement Caution
  3.4 Hydrophone Selection and Minimum Requirements
  3.5 Hydrophone Measurement System
      3.5.1 Hydrophone Amplifier
      3.5.2 Water Tank
      3.5.3 Positioning System
      3.5.4 Oscilloscope/Waveform Recorder
      3.5.5 Commercially Available Measurement Systems
  3.6 Force Balance Characteristics
      3.6.1 Constructing a Force Balance from Components
Section 4 CALIBRATION METHODS
  4.1 Introduction
  4.2 Traceability and the Calibration Process
  4.3 Outline of Calibration Procedures
  4.4 Calibrating the Force-Balance System
      4.4.1 Fundamental Force Balance Equations
      4.4.2 Reference Source Transducers
      4.4.3 Force Balance Calibration
      4.4.4 Force Balance Linearity Verification
      4.4.5 Spot Checks of Force Balance and Reference Source
      4.4.6 Calibration and Spot Checks of Working Source
  4.5 Local Laboratory Checks of Reference Hydrophone
      4.5.1 Arrival of the Reference Hydrophone
      4.5.2 Comparison Waveform Records
      4.5.3 Spot Checks of the Reference Hydrophone
  4.6 The Comparison Procedure for the Working Hydrophone
      4.6.1 Introduction
      4.6.2 Determination of End-of-Cable Loaded Sensitivity of
             the Working Hydrophone
  4.7 Spot Checks of Working Hydrophone
  4.8 Planar Scanning Checks of Hydrophone
  4.9 Hydrophone Calibration Above 20 MHz
Section 5 DIAGNOSTIC ULTRASOUND MEASUREMENT PROCEDURES
  5.1 Introduction
  5.2 Outline of Measurement Procedures
  5.3 Equipment and Setup
      5.3.1 Equipment Required
      5.3.2 Set-up
  5.4 Measurement of Intensities and Pressure in Non-Autoscan
      System
      5.4.1 Reference Location for Intensity and Pressure
             Measurements
      5.4.2 Select Operating Condition and Set Maximum Drive
             Voltage
      5.4.3 Determine the Beam Axis
      5.4.4 Find the Spatial Maximum Pulse Intensity Integral
      5.4.5 Verification of Maximum PII(j, v[mj], z[mjPII])
      5.4.6 Waveform Recording
      5.4.7 Calculate the Spatial-Peak Pulse-Average Intensity
             (I[SPPA])
      5.4.8 Calculate the Peak Rarefactional Pressure (p[r])
      5.4.9 Associated Parameters
      5.4.10 Calculate the Spatial-Peak Temporal-Average Intensity
             (I[SPTA])
      5.4.11 Measure the Ultrasonic Power
      5.4.12 Find the Spatial Maximum Derated Pulse Intensity
             Integral
      5.4.13 Verification of the Spatial Maximum
             PII[.3](j, v[mj], z[mIPII.3])
      5.4.14 Waveform Recording
      5.4.15 Calculate the Derated Spatial-Peak Pulse-Average
             Intensity (I[SPPA.3])
      5.4.16 Calculate the Derated Peak Rarefactional Pressure
             (p[r.3])
      5.4.17 Calculate the Derated Spatial-Peak Time-Average
             Intensity (I[SPTA.3])
      5.4.18 Measurement Methods for Equipment Which Produces
             Continuous Waveforms
  5.5 Measurement for Intensity and Pressure in Autoscan Mode
      5.5.1 Introduction to Autoscan Measurements in Combined
             Modes
      5.5.2 Measurement of I[SPTA.3] in Combined Autoscan Modes
  5.6 Power Measurements
      5.6.1 Force Balance Methods
      5.6.2 Alternate Power Measurement/Calculation Using a
             Hydrophone and Planar Scanning in Non-Autoscan Mode
APPENDICES
  A Statistical Considerations
  B Nonlinear Effects
  C Directivity of Hydrophone
  D Acoustical Output Quantities in Water and in Tissue Models;
    Derated Values
  E Water Degassing Procedure
  F Rationale for the Measurement of Selected Parameters
  G Determination of Control Settings Resulting in Intensity and
    Pressure Global Maxima
  H Hydrophone Calibration by Planar Scanning Technique
  I Consistency Checks
  J Measurement of I[SPTA] for a Combined Operating Mode
  K Rationale for Measurements in Water

Describes a set of measurement procedures for ultrasonic output parameters by setting forth definitions of quantities, primarily those relating to acoustic output levels, and specifying standard procedures for measuring the pertinent acoustic output parameters. It reflects the most current thinking on acoustic output measurement and will continue to evolve as the knowledge about acoustic output measurement increases.