Introduction Report 629 provides a brief introduction to the subjects of bandwidth and sampling_as relevant to the process of encoding component signals into digital form. In order to ensure that the total bit rate of the digital signal is not excessive@ it is clearly necessary to determine the bandwidths of the luminance and colour-difference signals which are adequate to provide high-quality broadcasting signals (which may be in the analogue composite form). Further@ when considering the filtering and sampling of component signals@ it is also necessary to bear in mind that proposals have been made to use such signals in digital form for purposes which could be more demanding than conventional broadcasting. In particular@ attention must be paid to the constraints imposed by modern programme production techniques@ taking into account the quality margin required by the increasing demand for picture-processing operations [Akrich and Zaccarian@ 1981]. In choosing the sampling parameters to be used for component signals@ the sampling frequencies are@ clearly@ closely related to the bandwidths of the component signals@ but other parameters are concerned with the picture sampling structure or structures. The number of bits necessary to describe each sample is discussed in ??. In order to handle a single byte stream in the studio when component coding is used@ time-multiplexing of the three byte streams is required. Some possible arrangements are discussed in ??