AS IEC 61672.1-2004 pdf – Electroacoustics- Sound level meters Part 1: Specifications.
2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. CISPR2 16-1:1999, Specification for radio disturbance and immunity measuring apparatus and methods – Part 1: Radio disturbance and immunity measuring apparatus IEC 60050(801)， International Electrotechnical Vocabulary – Chapter 801: Acoustics and electroacoustics IEC 60942, Electroacoustics – Sound calibrators IEC 61000-4-2， Electromagnetic compatibility (EMC) – Part 4: Testing and measurement techniques – Section 2: Electrostatic discharge immunity test. Basic EMC Publication IEC 61000-6-2:1999, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards – Immunity for industrial environments ISO/IEC GUIDE EXPRES:1995, Guide to the expression of uncertainty in measurement ISO Publication, ISBN 92-67-01075-1, International vocabulary of basic and general terms in metrology 3 Terms and definitions For the purposes of this standard, the terms and definitions given in IEC 60050(801)，the International vocabulary of basic and general terms in metrology, the Guide to the expression of uncertainty in measurement, and IEC 61000-6-2:1999, as well as the following apply. AII quantities are expressed in SI units.
3.6 maximum time-weighted sound level greatest time-weighted sound level within a stated time interval NOTE 1 Maximum time-weighted sound level is expressed in decibels (dB). NOTE 2 For maximum time-weighted sound level, example letter symbols are LAFmax. LASmax, LcFmax. and Lcsmax for frequency weightings A and C and time weightings F and S. 3.7 peak sound pressure greatest absolute instantaneous sound pressure during a stated time interval 3.8 peak sound level twenty times the logarithm to the base ten of the ratio of a peak sound pressure to the reference sound pressure, peak sound pressure being obtained with a standard frequency weighting NOTE 1 Peak sound level is expressed in decibels (dB). NOTE2 This standard provides specifications for measurement of peak C sound level; symbol Lcpeak. 3.9 time-average sound level equivalent continuous sound level twenty times the logarithm to the base ten of the ratio of a root-mean-square sound pressure during a stated time interval to the reference sound pressure, sound pressure being obtained with a standard frequency weighting
3.16 reference sound pressure level sound pressure level specified for testing the electroacoustical performance of a sound level meter NOTE Reference sound pressure level is expressed in decibels (dB). 3.17 reference level range level range specified for testing the electroacoustical characteristics of a sound level meter and containing the reference sound pressure level NOTE Reference level range is expressed in decibels (dB). 3.18 calibration check frequency nominal frequency, in the range from 160 Hz to 1 250 Hz, of the sinusoidal sound pressure produced by a sound calibrator that is used in checking and adjusting a sound level meter level linearity error at a stated frequency, an indicated signal level minus the anticipated signal level NOTE Level linearity error is expressed in decibels (dB). 3.20 linear operating range on any level range and at a stated frequency, the range of sound levels over which level linearity errors are within the tolerance limits specified in this standard NOTE Linear operating range is expressed in decibels (dB).
The signal processor includes the combined functions of an amplifier with a specified and controlled frequency response, a device to form the square of the frequency-weighted time- varying sound pressure, and a time integrator or time averager. Signal processing that is necessary to conform to the specifications of this standard is an integral part of a sound level meter. In this standard, a display device provides either a physical and visible display, or storage, of measurement results. Any stored measurement result shall be available for display by means of a manufacturer-specified device, for instance a computer with associated software. . 5.1.2 The performance specifications of this clause apply under the reference environmental conditions of clause 4. 5.1.3 For specifying the emission of, and susceptibility to, radio frequency fields, sound level meters are classified into three groups as follows: – group X sound level meters: self-contained instruments that include sound level measurement facilities according to this standard and which specify internal battery power for the normal mode of operation, requiring no external connections to other apparatus to measure sound levels; group Y sound level meters: self-contained instruments that include sound level measurement facilities according to this standard and which specify connection to a public supply of electric power for the normal mode of operation， requiring no external connections to other apparatus to measure sound levels; and group Z sound level meters: instruments that include sound level measurement facilities according to this standard and which require two or more items of equipment, which are essential constituent parts of the sound level meter, to be connected together by some means for the normal mode of operation. The separate items may be operated from internal batteries or from a public supply of electric power.