The system can issue a pure tone, tone twitter, narrowband noise and natural sound of the voice signal, and can adjust the loudness and frequency of the signals with some accuracy.

该系统能发出纯音、啭音、窄带噪声和自然声等声音信号，并可对信号进行一定精度的响度和频率调节。

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For RFI and narrowband noise interferences, this dissertation studies notch filter and spectrum equilibrium and USES them to suppress narrow jammings in signal domain.

对于RFI和窄带噪声干扰，本文研究了频域陷波和谱均衡两种方法，并将之应用到信号域来抑制窄带干扰。

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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。

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