What is BS EN 61260-3 - Octave-band and fractional-octave-band filters about?
BS EN 61260-3 is a safety standard on the periodic tests for octave-band and fractional-octave-band filters.
BS EN 61260-3 describes procedures for periodic testing of octave-band and fractional-octave-band filters that were designed to conform to class 1 or class 2 specifications given in IEC 61260-1:2014. The aim of BS EN 61260-3 is to ensure that periodic testing is performed in a consistent manner by all laboratories. The purpose of periodic testing is to assure the user that the performance of an octave band and fractional-octave-band filter conforms to the applicable specifications of IEC 61260-1 for a limited set of key tests and for the environmental conditions under which the tests were performed.
The extent of the tests in BS EN 61260-3 is deliberately restricted to the minimum considered necessary for periodic tests. Periodic tests described in BS EN 61260-3 apply to filters for which the manufacturer claims conformance to the specifications in IEC 61260-1:2014. Periodic tests in BS EN 61260-3 apply to filters for which the model has been, or has not been, pattern approved by an independent testing organization responsible for pattern approvals in accordance with the test procedures of IEC 61260-2.
Note: Because of the limited extent of the periodic tests, if evidence of pattern approval is not publicly available, no general conclusion about conformance to the specifications of IEC 61260-1 can be made, even if the results of the periodic tests conform to all applicable requirements of BS EN 61260-3.
Who is BS EN 61260-3 - Octave-band and fractional-octave-band filters for?
BS EN 61260-3 on the periodic tests for octave-band and fractional-octave-band filters is relevant to:
- Acousticians
- Testing authorities of periodic testing
- Manufacturers of the testing equipment and instruments
- Electronic engineers
Why should you use BS EN 61260-3 - Octave-band and fractional-octave-band filters?
IEC 61260:1995 did not provide any requirements or recommendations to account for the uncertainty of measurement in assessments of conformance to specifications. This absence of requirements or recommendations to account for the uncertainty of measurement created ambiguity in determinations of conformance to specifications for situations where a measured deviation from a design goal was close to the limit of the allowed deviation.
To remove this ambiguity, IEC Technical Committee 29, at its meeting in 1996, adopted a policy to account for measurement uncertainty in assessments of conformance in International Standards that it prepares. BS EN 61260-3 uses an amended criterion for assessing conformance to a specification. Conformance is demonstrated when (a) measured deviations from design goals do not exceed the applicable acceptance limits and (b) the uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty. Actual and maximum-permitted uncertainties of measurement are determined for a coverage probability of 95%.
Conformance to a performance specification is demonstrated when the following criteria are both satisfied:
- A measured deviation from a design goal does not exceed the applicable acceptance limit
- The corresponding uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty of measurement given in IEC 61260-1 for the same coverage probability of 95 %
Overall, BS EN 61260-3 is useful as it assists in demonstrating that every filter in set of filters are in working order since more extensive tests are only performed on a limited number of filters in a set of filters. The test is either performed as the measurement of the relative attenuation at the mid-band frequency of every filter in a set or alternatively, by measurement of the response to an exponential, sinusoidal sweep covering all filters in a set.
What’s changed since the last update?
Together with BS EN 61260-1:2014 and BS EN 61260-2:2016, BS EN 61260-3:2016 supersedes BS EN 61260:1996 which is withdrawn.
BS EN 61260-3:2016 replaces the first edition of IEC 61260 published in 1995 and its Amendment 1 published in 2001. BS EN 61260-3:2016 constitutes a technical revision.
BS EN 61260-3:2016 includes the following significant technical changes with respect to IEC 61260:
- The single document in the first edition of IEC 61260:1995 is now separated into three parts of IEC 61260 covering: specifications, pattern evaluation tests, and periodic tests
- IEC 61260:1995 specified three performance categories: class 0, 1, and 2 while the IEC 61260 series specifies requirements for classes 1 and 2
- In IEC 61260:1995, the design goals for the specification can be based on base-2 or base- 10 designs. In the IEC 61260 series, only base-10 is specified
- The reference environmental conditions have been changed from 20 °C/65 % RH to 23 °C/50 % RH
- IEC 61260:1995 specified tolerance limits without considering the uncertainty of measurement for verification of the specifications while the IEC 61260 series specifies acceptance limits for the observed values and maximum-permitted uncertainty of measurements for laboratories testing conformance to specifications in the standard
