These signals provide an important reference of the gain of antenna, the time reference, the phase reference and the frequency of carrier wave for generating stimulant echo signal.

这些信号分别为模拟回波信号的生成提供了天线增益大小、时间基准、相位基准和载波频率大小等重要的参考信息。

youdao

In order to increase the capacity of channel, the frequency of carrier wave moved to higher endlessly.

为了增加信道容量，载波频段不断地向高频方向移动。

youdao

But to the CW pulse signal with changing carrier wave frequency, common filter cannot achieve narrowband filter, whereas broadband filter cannot reach the request of the signal-noise ratio.

可是，对于载波频率不断变化的CW脉冲信号，普通的滤波器难以实现窄带跟踪滤波，而宽带滤波又不能达到提高信噪比的要求。

youdao