CONTENTS

      Annex  1  Data transmission at 2 400/1 200/600/300/150/75 bit/s over HF circuits using multi-channel voice-frequency telegraphy and PSK    
 1     System description           
      Annex  2  Data transmission at rates up to 3 600 bit/s over HF circuits  using a serial transmission modem    
 1     General      
 2     Modem operating modes 
        2.1     Semi-duplex forward error correction (FEC) mode
        2.2     Full-duplex FEC mode      
        2.3     Automatic repeat request (ARQ) mode      
 3     Technical characteristics of the modem     
        3.1     Modulation
        3.2     Transcoding           
        3.3     Frame structure     
        3.4     Error correction coding, interleaving           
        3.5     Spectrum of the modulated signal   
        3.6     Frequency error tolerance between transmission and reception HF carriers 
 4     Interfaces with other equipment    
        4.1     Modem interface with the data terminal      
        4.2     Modem interface with the transmitter and the receiver         
        4.3     Quality of performance of associated transmitters and receivers      
Annex 3  Transmission systems using PSK    
 1     Introduction      
 2     Theoretical questions       
        2.1     Selection of signals 
        2.2     Selection of a processing algorithm 
 3     Description of the system 
 4     Experimental investigations           
 5     Conclusions      
Annex  4  Mode/polarization diversity in high-frequency  radio data systems    
 1     Introduction      
 2     Conclusions      
Annex  5  Data transmission at rates up to 4 800 bit/s over HF circuits using a  serial PSK or quadrature amplitude modulation (QAM)  transmission modem    
      1     General 
 2
     Features     
 3     Specification     
 4     Block diagram of signal processing           
 5     Frame structure
 6     Coding rule and constellation diagram of 16-QAM           
 7     Test data    
Annex 6  High data rate waveforms 3 200/4 800/6 400/8 000/9 600/12 800 bit/s using a serial transmission modem over HF circuits    
 1     Introduction      
        1.1     Overview  
        1.2     Modulation
        1.3     Frame structure     
        1.4     Coding and interleaving      
        1.5     Operational features and message protocols           
        1.6     Performance capabilities    
        1.7     Associated communications equipment