Now, you can also shine light through many equally spaced slits -- this called a diffraction grating.

现在，您还可以通过许多等 间距的狭缝照射光线——这称为衍射光栅。

First, the incremental optical encoder from earlier can't read out an absolute angular  position because the wheel has 48 equally spaced spokes, and it can't discern one angle from the  next.

首先， 早期的增量式光学编码器无法读出绝对角度位置， 因为车轮有 48 个等距辐条，并且无法区分一个角度和下一个角度。