The training sequence of channel estimation in frequency domain should have flatspectrum, which can estimate channel fast and exactly.
作为频域信道估计的训练序列要求具有平坦的频谱特性，可以快速准确地对信道进行估计。
2
A sound flat tax policy will benefit people on all portions of the income spectrum.
单一税将有利于各个收入阶层。
3
Both the Flat-Field method and the method which utilize the solar radiation spectrum are used on reflectance, inversion in order to transform radiant brightness image into reflectance, image.