认知无线电(Cognitive Radio,CR)是一种智能频谱共享技术,第一用户信号检测是CR应用的前提。根据谱相关分析方法,利用信号非零循环频率处的谱线特征,可将信号从噪声背景中检测出来。为消除基底噪声,采用电子测量中的3σ准则对信号循环谱进行了消噪处理,便于实现检测,仿真论证了该方法在低信噪比下的有效性。 Cognitive Radio (CR) is an intelligent spectrum sharing technology. The first user signal detection is the precondition of CR application. According to the spectral correlation analysis method, the signal can be detected from the noisy background by using the spectral characteristics at the non-zero cycle frequency of the signal. In order to eliminate the base noise, the signal cyclic spectrum was de-noised by the 3σ criterion in electronic measurement, which is convenient for the detection. Simulation shows the effectiveness of this method at low signal-to-noise ratio.