Secondary phase modulated communications service via am broadcast stations

摘要: A SECONDARY COMMUNICATIONS SYSTEM FOR USE WITH AM BROADCAST STATIONS EMPLOYS ENCODING PREDEFINED MESAAGE WHICH MAY BE INITIATED BY DIALING PREDETERMINED DECIMAL DIGITS OR INITIATNG TOUCH-TONE SEQUENCES IN THE TELEPHONE SYSEM, CONVERTING THESE TO BINARY VOFR SEQUENCE "WORD," AND TRANSMITTING CODE WORD NON-INTERFERING PHASE MODULATION OF STATION CARRIER WAYS. SUBSCRIBER RECEIVERS, FIXED-TURNED CARRIER, ARE EQUIPPED SIMPLE RECOGNITION MEANS RESPONSE RECEPTION ONE MORE PREASSIGNED CODED "WORDS," ACTIVATE ASSOCIATED INDICATORS VISUALLY AUDIBLY ANNUNCIATE MESSAGES SUBSCRIBER.