IEC 60645-3:2020 pdf download

IEC 60645-3:2020 pdf download.Electroacoustics – Audiometric equipment – Part 3: Test signals of short duration
1 Scope
This part of IEC 60645 specifies a means of describing the physical characteristics, in terms of electrical waveforms, of audiometric reference and test signals of short duration and methods for their measurement. The object of this document is to ensure that audiometric stimuli of short duration are specified and measured in the same way and that the calibration of equipment using such signals is carried out using defined methods. This document does not describe the method of use of short-duration test signals.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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. IEC 60318-1, Electroacoustics – Simulators of human head and ear – Part 1: Ear simulator for the measurement of supra-aural and circumaural earphones IEC 60318-3, Electroacoustics – Simulators of human head and ear – Part 3: Acoustic coupler for the calibration of supra-aural earphones used in audiometry IEC 60318-4, Electroacoustics – Simulators of human head and ear – Part 4: Occluded-ear simulator for the measurement of earphones coupled to the ear by means of ear inserts IEC 60318-5, Electroacoustics – Simulators of human head and ear – Part 5: 2 cm 3 coupler for the measurement of hearing aids and earphones coupled to the ear by means of ear inserts IEC 60318-6, Electroacoustics – Simulators of human head and ear – Part 6: Mechanical coupler for the measurement on bone vibrators IEC 61260-1, Electroacoustics – Octave-band and fractional-octave-band filters – Part 1: Specifications ISO 389-6, Acoustics – Reference zero for the calibration of audiometric equipment – Part 6: Reference threshold of hearing for test signals of short duration
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http://www.electropedia.org/ ISO Online browsing platform: available at http://www.iso.org/obp 3.1 short-duration signal signal having a duration of less than 200 ms 3.2 click transient acoustic or vibratory signal whose frequency spectrum covers a broad frequency range, produced by applying a single rectangular electrical pulse to the terminals of the transducer Note 1 to entry: See Figure 1 and Figure 2.3.5 chirp short-duration signal in which the instantaneous frequency between two specified values varies monotonically for the duration of the signal 3.6 upward chirp chirp which presents the low frequency components in the chirp before the high frequency components 3.7 broadband chirp chirp that has a specified electrical amplitude spectrum covering at least 5 octaves of the normal audible frequency range, Note 1 to entry: See Figure 5. 3.8 octave-band chirp chirp with an electrical amplitude spectrum corresponding to the amplitude-frequency characteristic of an IEC 61260-1 octave-band filter with a specified center frequency 3.9 condensation signal short-duration signal, the initial wave of which causes an over-pressure relative to ambient pressure, or an over-force relative to the static force at the plane of the output port of the transducer 3.10 rarefaction signal short-duration signal, the initial wave of which causes an under-pressure relative to ambient pressure, or an under-force relative to the static force at the plane of the output port of the transducer 3.11 alternating polarity signal series of short-duration signals, consisting of rarefaction and condensation signals in alternating order3.12 initial wave of a click stimulus signal first half wave of the stimulus signal, the amplitude of which is larger than 0,5 times the amplitude of the next half wave with opposite polarity 3.13 duration of initial wave of a click stimulus signal time interval between the two zero crossings of the initial stimulus signal wave 3.14 duration of a tone-burst time interval between the half maximum amplitude points on the rising and falling portions of the envelope of the electrical tone-burst signal Note 1 to entry: See Figure 3, key 4.