SECURE SCA BROADCASTING SYSTEM INCLUDING SUBSCRIBER ACTUATED PORTABLE RECEIVING TERMINALS
 Inventors: Aubry S. Forman, Toledo, Ohio;
Charles A. Schultz, Jr.; John F.
Schultz, both of Gainesville, Fla.
 Assignee: Digital Data, Inc., Sylvania, Ohio
 Appl. No.: 848,269
 Filed: Nov. 3,1977
Related U.S. Application Data
 Division of Ser. No. 675,504, Apr. 9, 1976, Pat. No. 4,112,369.
 Int. CI.* H04I9/02
 U.S. CI 178/22; 340/149 R;
 Field of Search 178/22; 340/154, 149 R
 References Cited
U.S. PATENT DOCUMENTS
3,387,268 6/1968 Epstein 340/154
3,478,169 11/1969 Saito 179/15
3,611,294 10/1971 O'Neill et al 340/154
3,654,604 4/1972 Crafton 340/147 R
3,716,835 2/1973 Weinberg et al 340/154
3,798,360 3/1974 Feistel 178/22
3,962,539 6/1974 Ehrsam et al 178/22
4,004,089 1/1977 Richard et al 178/22
Primary Examiner—Samuel W. Engle
Assistant Examiner—S. A. Cangialosi
Attorney, Agent, or Firm—Wilson, Fraser, Barker &
A secure information broadcasting system including a central transmitting station for encoding data in binary form utilizing a keyword and transmitting a FM-SCA signal phase shift modulated by the encoded data. Each of a plurality of portable receiving terminals has an identification number stored therein. When a subscriber desires to display the broadcast information on his terminal, he enters a unique password which is combined with the identification number to generate the keyword. The keyword is utilized to decode the received binary data. The portable terminal includes a receiver for decoding the phase shifted FM-SCA signal into the encoded binary data; a keyboard for entering the password, information and display commands; an alphanumeric data display; a processor responsive to the inputs from the receiver and the keyboard for performing selected arithmetic and logic operations to generate output data to the data display and a bus connecting the circuits of the portable terminal for parallel signal flow.
7 Claims, 12 Drawing Figures