从线性反时间混沌理论出发,提出一种混沌信号宽带模糊函数算法。在现有的宽带模糊函数算法中,时间尺度变换的混沌信号需要极大的运算量来得到,难以适应需要实时处理的工程环境。根据反时间混沌理论,噪声脉冲驱动下的线性系统能产生反时间混沌信号。通过不同时钟频率的数字系统产生脉冲信号,然后以此脉冲信号驱动相应的线性系统直接产生延迟和时间尺度变换后的反时间混沌信号。最后可通过相关处理方便地计算相应混沌信号的宽带模糊函数。通过理论推导和数值仿真阐述及分析该模糊函数算法,证明了该方法数字模拟混合的结构使其能方便应用于实际的工程之中。
This paper develops a reverse-time chaos based scheme for calculating wideband ambiguity function (WBAF) of a chaotic signal. In the direct implementation, the formulation of the time-scaling chaotic signal takes much computational load and its accuracy determines the quality of the calculated AF diagrams. By exploring the reverse-time chaos theory, it is found in this paper that the time-delay and time-scaling versions of chaotic signal can be generated directly by linear system. With this observation, the WBAF diagrams can be accurately obtained by following correlation operation. A distinct characteristic of the proposed scheme is that the generation of the time-delay and time-scaling versions is implemented in analog way, while the correlation operation can be implemented in digital way. This mixed analog-digital structure provides the proposed scheme with implementation advantages and practical applicability.