PROCESS FOR TRANSMITTING ADDITIONAL INFORMATION IN AN A.M. RADIO SIGNAL

摘要

For transmitting additional information in an AMradio signal, initially, at the transmitting end an AMradio signal carrier is modulated in its phase positionby means of a digital, coded additional informationsignal. At the reception end the AM radio signal carrieris phase-modulated, the additional information signalacquired is decoded and the decoded additional infor-mation is used for tuning, switching or playback. Theadditional information (PI, PS, AF, AFT, TP, TA, TMC, RT)of the additional information signal is divided up intoa cyclically repeated number of groups to form in eachcase two information blocks of identical length. Eachinformation block has an information word and a checkword comprising in each case a specific number of databits, the two check words of each group having differentoffset words superimposed on them. These offset words areused at the reception end to synchronize the informationblocks.