Non-uniform sampling and the zero crossing distribution

In order to increase the security of the normal Time–Division Multiplex system, it is proposed that the channels should be multiplexed in accordance with a predetermined code sequence which can easily be altered and which is known only to the sender and the receiver. One possible method of achieving this form of coding is to employ non uniform sampling of the signal sources prior to the transmission. In Part I of the thesis we discuss the theoretical aspects of non-uniform sampling and assess its practical implications in the light of the above application. The points at which a random function intersects the zero level finds many applications in applied science and engineering. This constitutes what is known as the Zero Crossing Problem, which remains today one of the most intractable problems in the theory of noise for which no satisfactory solution has yet been found. In Part II a study of this problem is presented. The study surveys some of the past research carried out on the subject and discusses some new ideas and techniques.