SN EN 60118-0 : 1993 AMD 1 1994

Gives the measurement of physical performance characteristics of airconduction hearing aids based on a free-field technique and measured with an ear simulator. Specifies methods of measurement for the evaluation of the electroacoustical characteristics of hearing aids which are practical and reproducible, and consequently they are based on fixed parameters chosen, to a certain extent, arbitrarily and considered when comparisons are made between test results for hearing aids of different models and manufacture. Includes harmonic and intermodulation distortion and illustrates examples of the determination of the equivalent input noise level of a hearing aid, quadratic type non-linearity and cubic type non-linearity.