Highly Reliable Information and Communication Networks.

在扩频通信系统中，对载波频偏具有较强鲁棒性的多进制扩频通信系统进行了研究。当存在载波频率偏移时，众所周知，发射的信号功率降低，并且在接收端出现螺旋状分量。为了应对这些现象，要求接收端倍频后的频谱1)展宽良好，2)没有峰值，3)具有低功率密度谱。作为实现这些性质的正交码，由M序列构成核心矩阵的循环H矩阵是充分的。与针对这些码设计的接收机相结合，发现整个系统对载波频偏具有很强的鲁棒性，并研究了Hadamard码自检验器的设计。众所周知，Hadamard码在通信系统、信号处理等方面非常有用。然而，针对这些码的自检校验器的设计从未被提出过。结果表明，当Hadamard矩阵的度数为形式p=8m+3的素数时，可以利用差集的性质进行这种设计。最后，在大规模集成电路测试的研究中，具有强随机性的测试输入是非常重要的。从二维随机平面(M-平面)切出的部分分数的各种随机性已被研究，具有相当优异的性质，优于从一维M序列得到的序列。

As for Spread Spectrum (SS) Communication Systems, M-ary SS communication systems robust to carrier frequency offsets have been investigated. When there exist carrier frequency offsets, it is known that transimmted signal powers are decreased and sprious components appear at the receiving ends. In order to cope with these phenomina, it is required that the frequency spectrums after multiplication process at the receiver are 1) well spread, 2) have no peaks and 3) have low power desity spectrums. As orthogonal codes to realize these properties, cyclic H matrices, whose core matrices are made of M sequences are found to be adequate. Togehter with receivers designed for these codes, it is found that the total system is quite robust to carrier frequency offsets.The design of self-checking checkers for Hadamard codes have also been investigated. Hadamard codes are known to be quite useful in communication systems, signal processings and so forth. However, self-checking checker design for these codes have never been proposed. It is found that this design can be made by using the properties of difference sets when the degreee of Hadamard matrices are prime numbers of the form p=8m+3Finally, in the study of LSI tests, it is very important to have test inputs with strong randomness properties. Various randomness properties of partial fractions cut out from 2 dimensional random plane (M-plane) have been investigated to have quite excellent properties, superior than the sequences obtained from 1-dimensional M sequences.