Interleaved Block Coding Tests over VHF and HF Channels

An operational one-way error correcting system has been constructed and tested at teleprinter speeds. The short onethird rate code was heavily interleaved and decoded using "minimum distance decocling," All system functions, including timing controls, were tested under single and dual diversity over 1300-km VHF and 1500-km HF paths, subject to a wide range of binary error rates. Test results showed differences in coder performance between the VHF and HF channels. Statistics of a secondary decoder output, called the inversion count, are given in a form useful for error detection, word erasure, or other feedback applications.