Test results of a time-dispersed forward error control system

The purpose of this correspondence is to describe some results of a recent test of a forward error control system over operational HF radio circuits. This system employed simple algebraic block codes in conjunction with bit interlacing. In the system tested, symbol separation amounted to approximately one second, thereby allowing single bursts of two seconds to be corrected. Of course, many bursts of shorter duration are also correctable. Tests were conducted using two tone channels on a DCS HF link operating between NAVCOM centers located at Rtockton, Calif. and Cheltenham, Md. The basic test configuration is shown.