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

摘要

In order to transmit additional information with an A.M. radio signal, thephaseposition of an A.M. radio signal carrier is first modulated on the emittersidewith a digital, coded additional information signal. On the receiver side, theA.M. radio signal carrier is phase modulated, the recovered additionalinformation signal is decoded and the decoded additional information is usedfor tuning, switching and/or reproduction purposes. The additional information(PI, PS, AF, AFT, TP, TA, TMC, RT) of the additional information signal issubdivided into a cyclically repetitive number of groups having each twoinformation blocks of the same length. Each information block has aninformation word and a checking word composes of a determined number ofdata bits, different offset words being superimposed upon both checkingwords of each group. These offset words are used on the receiver side forsynchronizing the information blocks.