Abstract :
Digital equipment introduces new types of distortions. Some can be evaluated with special test signals, but for the most part subjective evaluation is the only method of determining the visual quality level of the signal. Therefore an understanding of the causes of these distortions and the steps that can be taken, both in the design and operation of equipment, to reduce their effects is useful if the full benefits of digital signal processing equipment is to be realised. As equipment is gradually converted from analogue to digital the distortions associated with analogue equipment tend to disappear, to be replaced by unique distortions and limitations of digital signal processing equipment. Using the available digital technology these may be made small compared with analogue technology. The key performance parameters can be determined at the system design level before any of the components of the system are selected or implemented. The remaining distortions such as severity of quantising noise, differential phase and gain due to crosstalk, are determined by a single component-the analogue to digital converter
