CONTENTS

RECOMMENDATION  ITU-R  F.1821     1
Characteristics of advanced digital high frequency (HF) radiocommunication systems     1
Scope     1
Annex 1     2
1 Introduction  2
2 Token passing protocols  3
3 Wideband modems  4
        3.1 Multichannel approach  4
                  3.1.1 Independent sideband (ISB) operation  4
                  3.1.2 Operation in non-contiguous channels  4
        3.2 Digital Radio Mondiale (DRM) 5
        3.3 Characteristics  6
4 Conclusions  6