The frequency associated with the first mode is sometimes called the fundamental frequency . 和第一振模相联系的频率有时叫做基频。
Fundamentals and overtones of other bands in this region are not difficult to recognise . 在这个区域中其他谱带的基振动或信频是不难识别的。
The high frequencies are not emitted, the effect of frequency-selective propagation is not very apparent . 没有激发高频，频选传播不很明显。
With ordinary photocells, one can pick up the frequency between two different lasers . 用普通光电池，人们就能够深测到两个不同的激光之间的拍频。
With ordinary photocells, one can pick up the frequency between two different lasers . 用普通光电池，人们就能够探测到两个不同的激光之间的拍频。
For the fundamentals, b'-b"is very small and therefore the lines are almost equidistant. 对于基频振动来说，B-B很小，因此谱线是几乎等距离的。
Two can indeed easily be explained as first overtones(see table 115)which occur strongly because of fermi resonance . 另外两条的确很容易解释为第一泛频（参看表115），它们的强度由于费密共振而增强。
However, the earliest long-period seismographs recorded dispersive waves with large transverse displacement components in the main tremor . 但是，最早期的地震记录，就记录下了主震中具有很大横向位移分量的频散波。
If the sampling frequency is less than this, we can expect a serious distortion of output frequency which is generally referred to as aliasing . 如果取样频率小于此数，那么输出频率就要产生严重畸变，通常假频指的就是这种情况。
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