A Digital Data Interleaver

Abstract

Many future space programs such as Space Shuttle contain a number of payloads, each generating its own digital data stream. It is frequently desirable to combine these data streams in a composite serial stream for the telemetry down link. The circuitry for combining these data streams should be as transparent as possible to the design and operation of individual data source subsystems. A concept is described for interleaving the data of several sources without any subsystem synchronization, few limitations on data rates, a no restrictions on formats. All data are accepted without loss and the composite stream is formatted in accordance with IRIG standards. The interleaver requires the use of artificial fill data to assure the possibility of accepting and formatting asynchronous data symmetrically; therefore, methods of error detection and correction of fill words are discussed to ensure nonambiguity of data and fill work.