Racal-Datacom, Inc.

Racal-Milgo Limited

Jong-Keung Cheng

Ming-Luh Kao

A combined data compression/error correction system suitable for use in synchronous communication utilizes a data compressor to produce variable rate compressed data from synchronous data. The variable rate compressed data is applied to a FIFO memory which is monitored to determine when the amount of data in the FIFO drops below a predetermined threshold. When it drops below this threshold, an error correction code generator generates a separator character and an error correction code which is appended to the compressed data in the FIFO. Thus, the additional bandwidth created by data compression is used to provide enhancement to the data integrity by providing a variable level of error correction varying in accordance with the free bandwidth generated by the data compressor.

Data compression with error correction

A microprocessor-based system is provided with a non-volatile store (such as a PROM) which stores a bootstrap program, a non-volatile store (such as an EPROM) which stores one or more program overlays, and a programmable volatile store (such as a RAM) which can be written into and read from. When the system is powered up, the microprocessor executes the bootstrap program out of the PROM. The bootstrap program includes instructions which copy the program instructions stored in the EPROM into the RAM. The microprocessor then executes the program instructions out of the RAM. Program instructions may be stored in the EPROM in a plurality of overlays, and individual overlays selected by either the bootstrap program or instructions contained in another overlay may be selectively loaded into the RAM for execution. The EPROM is addressed by a programmable counter which appears to the microprocessor as an input/output device to be written into.

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Miami, FL, United States of America

Jong-Keung Cheng