Name: ASA S3.42 Part 2 PDF - Engineering Standards Download
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ASA S3.42 Part 2 – Testing Hearing Aids – Part 2: Methods for characterizing signal processing in hearing aids with a speech-like signal (a nationally adopted international standard)

Scope

This American National Standard specifies a test signal designed to represent normal speech, theInternational Speech Test Signal (ISTS), together with the procedures and the requirements formeasuring the characteristics of signal processing in air-conduction hearing aids. The measurementsare used to derive the estimated insertion gain (EIG). For the purposes of characterizing a hearing aidfor production, supply and delivery, the procedures and requirements to derive the coupler gain on a2 cm3 coupler as defined in IEC 60318-5 are also specified.

The procedure uses a speech-like test signal and the hearing aid settings are set to thoseprogrammed for an individual end-user or those recommended by the manufacturer for a typical enduserfor a range of flat, moderately sloping or steep sloping audiograms, so that the measuredcharacteristics are comparable to those which may be obtained by a wearer at typical user settings.The purpose of this standard is to ensure that the same measurements made on a hearing aidfollowing the procedures described, and using equipment complying with these requirements, givesubstantially the same results.

Measurements of the characteristics of signal processing in hearing aids which apply non-linearprocessing techniques are valid only for the test signal used. Measurements which require a differenttest signal or test conditions are outside the scope of this standard.

Conformance to the specifications in this standard is demonstrated only when the result of ameasurement, extended by the actual expanded uncertainty of measurement of the testing laboratory,lies fully within the tolerances specified in this standard as given by the values given in 6.1.Measurement methods that take into account the acoustic coupling of a hearing aid to the individualear and the acoustic influence of the individual anatomical variations of an end-user on the acousticalperformance of the hearing aid, known as real-ear measurements, are outside the scope of thisparticular standard.