4 . we demonstrate the existence of bimodal noise really by studying narrowband bimodal process in detail , that provides the possibility for evaluating the performance of non - coherent detection in communication system with bimodal noise 通过对窄带双模过程的详细研究,说明了双模噪声的现实存在性,为准确评估双模噪声下通信系统的包络检波性能提供了可能。
/ 4 - dqpsk which is a modification of qpsk modulation . it is a linear narrowband technology which has been widely employed in mobile communication system , satellite communication system . it possesses features of high spectrum utilization ratio , better spectrum specification , stronger anti - fading performance and applicability to non - coherent detection / 4 - dqpsk是qpsk改进方式,它是一种线性窄带数字调制技术,被广泛应用于移动通信和卫星通信中,其突出特点是频带利用率高、频谱特性好、抗衰落性能强、可进行非相干解调。