BUS STRUCTURED SOFTWARE FOR A MODERN PCM DECOMMUTATOR

Abstract

The expanding requirement in Modern Telemetry Systems for Real-Time Data Processing has necessitated the commutation of a vast majority of the data processing functions into Front End Processors. Even the fastest of Host Processors has proven incapable of keeping pace with high speed data rates (up to 4 Megawords). The commutation of processing power into the telemetry front end has elicited the employment of distributive processing techniques in order to attain the desired throughput. A distributive processing system architecture achieves high processing throughput by apportioning data analysis functions. By defining and programming unique processing nodes to selectively acquire, distribute, compress, and/or convert data, extensive simultaneous operations are executable. Hardware merged bus structures have lent themselves conveniently to this method of data distribution and control. Conversely, conventional software structures are unsuited to distributive processing architectures which must support a broad spectrum of modular configurations. Primarily, this is evidenced when the composite system software must be repetitively customized as additional processing power or new capabilities are incorporated. Composite software that delivers a high degree of system configuration adaptability is nominally large and complex, is limited in application, depletes system memory resources and complicates sustaining software maintenance. In addition, an undesirable human interface is normally unavoidable with composite software since it requires that the user learn the specific front end system’s terminology and individual components. Bus Structure Software consigns itself to effectively support distributive processing techniques providing for adaptive system configurations. This disquisition will address the concepts of bus structured software and its application to distributive processing. Furthermore, this paper will discuss the architectural capability to service a wide range of telemetry users without specialized system tailoring. A typical implementation of this convention, the Advanced Decommutation System (ADS) designed by LORAL DATA SYSTEMS, San Diego, California will also be presented.