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。