It has been pointed out that communication systems having wideband signal waveforms have certain advantages over the conventional narrowband systems. This report describes the results of a research program which examined in detail the information efficiency of wideband systems. The results presented in this report fall into three major categories: (1) analysis of systems utilizing linear receivers (i.e. synchronous receivers , etc.), (2) analysis of system utilizing non-linear receivers, and (3) analysis and description of methods which can be used for realizing certain optimum and sub-optimum wideband receivers. The development of these topics is based on the geometrical concept of a signal space. These signal space concepts along with certain definitions are discussed in Chapter II. In Chapters III, IV and V wideband systems utilizing linear receivers are analyzed and the performance of these systems is determined for certain important types of noise which may be added in this communication channel. It is shown that in most cases, optimum performance cannot be obtained through the use of linear receivers. Non-linear techniques which are capable of supplying improved performance are discussed in detail in Chapters VI and VII. From the consideration of the types of noise which one may expect to encounter when using wideband systems, it is apparent that a relatively sophisticated approach is required in order to obtain the required physical realizations„ Certain methods which appear to be useful in obtaining these realizations are discussed in Chapter VIII and IX. Because the nature of the interference, in general, will not be known in detail to the designer, certain adaptive techniques are incorporated.
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