| 摘要 |
In short-wave radio transmission, in particular in telex connections, measures must be provided for data security in the form of FEC or ARQ in the case of more stringent requirements in terms of the quality and availability of the transmission path. As in the radio bit rate upwardly limited by short-time fading, a correspondingly lower useful bit rate must be accepted for the sake of data security. A further reduction in the essentially available radio bit rate for the useful information is produced with the additional use of a diversity. To enable transmission which is interference-proof even to specific extraneous interference, it is proposed that, along with data security measures in the form of FEC or ARQ and an "in-band diversity", the frequency of the radio frequency carrier (fr) is additionally modified in pseudo-random fashion in a fast changeover matched to the information block pattern of the information and the reciprocal time shift of the information transmitted simultaneously in the in-band diversity channels is to be selected at least equal to the shift interval of the radio carrier frequency. <IMAGE>
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