A study of optimum multiplexing systems



Journal Title

Journal ISSN

Volume Title



A general model was derived which permits analysis of performance of general multiplexing systems. The model also permits synthesis of many interesting new multiplexing systems. The model was used to determine optimum multiplexing systems for various channels. For an additive white Gaussian noise channel it was shown that only equipment simplicity is important in comparison of multiplexing system quality. Systems based on orthogonal binary waveforms and real exponentials were proposed as best satisfying this subjective criterion. For a bandlimiting channel prolate spheroidal waveforms were shown to achieve the optimum performance. Such waveforms have other undesirable characteristics. Certain frequency division multiplexing systems can achieve essentially the same bandwidth and are much more attractive from other viewpoints. For a peak-limiting channel binary coded waveforms were shown to be optimum. A study was made of channels with a combination of constraints. In order to maximize output signal-to-noise ratio for many important channels, it was shown that the multiplexing system should be designed so that the product of the peak-to-average power and bandwidth is minimized. Some bounds were derived for this parameter.