This paper discusses a technique of sharing extra storage buffers among a number of nodes (for example concentrators) or among a number of output lines in a single node (for example, in a message switching center). Buffer sharing can be used to reduce the probability that a message is blocked, while at the same time buffer storage cells can be conserved. In addition, buffer sharing reduces sensitivity to variations in traffic. Although the improvement increases as the size and complexity of the buffer sharing system increases, significant improvement is possible even for relatively simple systems. In modeling these systems, a precise model would use data unit storage. However, a simpler model using message storage is easier to analyze. A linear relationship can be used for converting message storage into data unit storage.

Phase-locked oscillators (PLO's) have two main areas of application: demodulation and synchronization. In this tutorial paper, a simplified approach to designing PLO's for synchronization is described. In particular, some tradeoffs which can be made between such characteristics as capture range, jitter attenuation, time to lock, and phase offset are presented. As examples of this approach, the method is applied to three circuits in a Picturephone®video coder-decoder (CODEC). The application of an optimum phase comparator is also described.