7 - Signal degradation

Abstract

The term signal degradation is used to describe the fact that changes in the amplitude or shape of a signal have taken place as a result of that signal being subjected to some unwanted process while being transferred through the system. Sometimes such degrading is unavoidable. However, good design practices should minimize much signal degrading. A logic circuit diagram is used to show the theoretical organization and interconnections between the various logic devices used in the construction of a microelectronic system. It does not indicate the actual physical layout of the system, but is arranged so that the operation of the system as a whole might be clearly followed. For a given logic circuit, it is possible to have many different physical layouts, that is, position and orientation of devices, and size of circuit board. The ideal physical layouts are those that keep the interconnecting wiring to a minimum with conductors of the shortest possible length, but factors such as the need for testing and fault finding might call for slight deviations from the ideal. Given these constraints, there remain a number of different physical layouts that provide equal electrical performance.