In an amplitude grating system of small grid pitch, the diffractive light is the main cause to deteriorate the contrast and sinusoidal property of Moiré signals.

在国内外普遍使用的细栅距幅光栅叠栅条纹系统中，衍射效应是很明显的，这是造成叠栅条纹信号的衬比（度）和正弦性不好的主要原因。

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Well,if you go back to the formation of musical notation from the ninth through the twelfth centuries we see that very early on these two dimensions of music the two axes of music that we talked about before pitch vertically and duration horizontally, are in place and we have these spots in this grid.

回顾一下从公元九世纪至二十世纪,音乐记谱法的历史形成过程,我们可以看出,音乐的两个维度,就是我们之前提到的音乐的两个轴,纵轴是音高,横轴是时值,在早期已经存在了,我们在这样的网格上用点记录

耶鲁公开课 - 聆听音乐课程节选