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这个应该跟IEC 60601-1-8差不多，摘录其中单脉冲特征的描述（Characteristics of the Individual Pulses）" ...IEC 60601-1-8 requires that an individual sound pulse must have a fundamental frequency (musically known as pitch) somewhere between 150 to 1000 Hz, and there must be at least four harmonic sounds from 300 to 4000 Hz. Figure I shows a visible example of an audible sound that meets these requirements. The peak to the far left in Figure I is the fundamental frequency of the sound, and the four peaks to the right of the fundamental peaks represent the harmonic tones. To the ear, the resulting blended sound would be similar to hearing four different musical notes played at the same time. A final requirement for the sound pulse characteristic is that the sound level (measured in dB) of the four harmonic tones must be within ±15 dB of the fundamental frequency tone. ...”，完整描述见附件"Audible Alarm in Medical..."。 附件“MedicalAlarmExample.png”是人工合成的满足要求的一个例子，基频为770Hz, 包括2~5次谐波，基频和各次谐波的幅度一样。脉冲持续时间是200ms, 然后停200ms. 上升时间理解为声音由小变大（fade in）的时间为脉冲串持续时间的10%，设置为20ms, 下降时间可理解为零吧？产生的WAV波形文件见附件，可听听效果。 |
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