The reason for the differences in the spectral purity with regard to longitudinal mode content of the lasers is still not clear . 关于这种激光器中，造成纵模成分的纯度有差别的原因，现在仍不清楚。
2.
The sampling clock generator must also have adequate spectral purity 时钟发生电路固有的抖动应该足够小。
