How to set the additional filtering? Input a figure 1, 2, 3…?

这里的过滤是纯化器的意思，但还有其它的类型的附加过滤器，这只是针对气路上的，在英文中，数据和数字过滤也是这词，所以先要区别是仪器程序还是气路或电路，这是纯化器章节中的，通常我会在纯化器后段，添加我们用户自己的过滤器，属于颗粒型的，还有聚结型的，和冷凝水型的，根据需要，这通常是可选项，用户自己配置。

The LOW NOISE setting applies additional filtering (typically a factor of two) to the signal

按字面意思，当使用LOW NOISE设定时，会对信号产生额外过滤，一般是两倍

通常对于过滤降噪，是以倍数计，a factor of two　是2X（或x2），　原有过滤x2，其实是增加了一倍過濾，噪声相对地减少了一半(1/2)

According to these simple sentenses, there are only 2 settings - FAST/LOW NOISE. "a factor of 2" is just describing the filtering effect of the LOW NOISE setting. It doesn't mean that the user may control the degree of filtering freely.

有点印像了。 In signal filtering, it seems that +/- 5dB (or 10dB ???) would increase or reduce the signal by 2 times ???

A second thought, it seems that it may not be electronic signal filtering, but a chemical filtering.

所以先要区别是仪器程序还是气路或电路

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