Beats With Two Tone Generators
双音发生器的拍频现象
Two tunable electronic tone generators can be used to demonstrate the phenomenon of beats.
The image below is the beat pattern produced by the two two small loudspeakers side-by-side that are driven by two tone generators.
下图显示的是由两个并排放置的小扬声器产生的拍频现象，这两个扬声器分别由两个音调发生器驱动。
When the two tones are close together in frequency, the ear hears what seems to be a single pitch, and the measurement above gives a frequency of 231 Hz. But the tone pulses in loudness at the beat frequency, the difference between the two frequencies. Measuring the period of the pulsing gives a beat frequency of about 8Hz. We don't get an accurate frequency of either tone, but we know that the two tones center about 231 Hz and that they are 8 Hz apart in frequency.
当两个音调的频率接近时，耳朵听起来像是一个单一的音调，上述测量给出的频率为231 Hz。但两个音调在响度上以拍频脉动，即两个频率之差。测量脉动的周期得到一个约为8 Hz的拍频。我们无法准确测定每个音调的频率，但知道两个音调中心大约在231 Hz，且它们的频率差为8 Hz。
两个可调的电子音发生器可用于演示拍现象。
Hearing concepts
Traveling wave concepts
索引 声学概念 波动概念
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