放大器噪声相关系数C的一种测算方法

E_■,I_a和C是放大器E_■—I■噪声模型的完备噪声参数.噪声是一个随机过程,因而C不能直接测得,本文讨论一种测算C的概率方法.

空间各向同性均匀噪声场中的子阵输出噪声相关性

阵列分子阵后由于子阵存在方向性,导致子阵输出噪声相关系数以及相关半径难以准确估计,从而严重影响阵列性能。针对这一问题,提出了共线子阵在空间各向同性均匀噪声场中输出噪声相关系数的解析计算方法。将噪声相关性计算公式中的波束响应项用子阵加权向量表示,再利用共线子阵的对称性对双重积分进行化简,最终得到不含积分项的解析解。利用该方法,分析了子阵不同参数对输出噪声相关性以及子阵波束形成的影响,结果表明,子阵阵元数、子阵的波束指向角以及子阵中心间距的对输出噪声相关性有重要影响,而子阵波束的旁瓣对噪声相关性的影响较小。数值仿真验证了噪声相关性计算方法的有效性以及相关结论的正确性。

Aperiodic stochastic resonance in Schmitt trigger

By the use of cross-correlation measures, the response of a symmetric Schmitt trigger (ST) driven by a random binary signal and white Gaussian noise is investigated. The results show that the information transmission can be enhanced when a certain amount of noise is presented, i.e., aperiodic stochastic resonance (ASR). Then, the influence of signal amplitude and the ST threshold on ASR is examined, the applicability of the ST in reducing the noise level of random signal transmission and improving the quality of output signal via ASR effect is illustrated. This research is of great interest in the field of digital communications.