电声学.助听器.第4部分:助听器的声频感应线圈.磁场强度

[中文适用范围]： 该国际标准适用于在音频下产生交变磁场的音频感应环路系统，旨在为使用感应拾波线圈操作的助听器提供输入信号。该标准规定了助听器音频感应环路的场强要求，这将在助听器不过载的情况下提供足够的信噪比。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（参见附件 B）、应向系统操作员和用户提供的信息（参见附件 C）以及其他重要考虑因素。该标准没有规定对环路驱动放大器或相关麦克风或音频信号源的要求，也没有对 ITU-T P.370 范围内的电话听筒等设备产生的场强规定要求。 [外文原描述]： Applies 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. The 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.