电声学.助听器.第4部分:助听器的声频感应线圈.系统性能要求

[中文适用范围]： IEC 60118 的这一部分适用于在音频下产生交变磁场的音频感应环路系统，旨在为使用感应拾音线圈（拾音线圈）运行的助听器提供输入信号。在整个标准@中，假设与其一起使用的助听器符合 IEC 60118 的所有相关部分。该标准规定了助听器用途的音频感应环路的场强要求@，这将提供足够的信号到-助听器不过载的情况下的噪声比。该标准还规定了可接受清晰度的最低频率响应要求。规定了测量磁场强度的方法@并给出了有关适当测量设备的信息（见附件B）@应向系统操作员和用户提供的信息（见附件C）@以及其他重要考虑因素。本标准没有规定 IEC 62489-1@ 中涉及的环路驱动放大器或相关麦克风或音频信号源@的要求，也没有规定 ITU-T P 范围内电话听筒@等设备@产生的场强的要求。 .370. [外文原描述]： IEC 60118-4:2014 is applicable to audio-frequency induction-loop systems producing an alternating magnetic field at audio frequencies and intended to provide an input signal for hearing aids operating with an induction pick-up coil (telecoil). Throughout this standard, it is assumed that the hearing aids used with it conform to all relevant parts of IEC 60118. This standard specifies requirements for the field strength in audio-frequency induction loops for hearing aid purposes, which will give adequate signal-to-noise ratio without overloading the hearing aid. The standard also specifies the minimum frequency response requirements for acceptable intelligibility. Methods for measuring the magnetic field strength are specified, and information is given on appropriate measuring equipment (see Annex B), information that should be provided to the operator and users of the system (see Annex C), and other important considerations. This standard does not specify requirements for loop driver amplifiers or associated microphone or audio signal sources, which are dealt with in IEC 62489-1, or for the field strength produced by equipment, such as telephone handsets, within the scope of ITU-T P.370. This third edition cancels and replaces the second edition published in 2006. This edition constitutes a technical revision which includes the following significant technical changes with respect to the previous edition: Addition of Annexes G, H and I where more information is provided about practical considerations and methods of measurement.