Secure television transmission system

Apparatus for secure transmission and reception of a signal, said signal including a plurality of first lines with each first line comprising a synchronization portion followed in time by a first data portion, said data portion comprising at least sequentially occurring first and second data segments, comprising:

• 1. first data storage means having first and second storage locations with each location having sufficient storage capacity to store data representing at least one line of said signal;
• 2. control apparatus for alternately storing data representing selected lines of said signal in and alternately reading data representing selected lines of said signal from said first and second storage locations to produce modified lines corresponding to each of said first lines, each modified line consisting of a synchronization portion and third and fourth data segments sequentially following said synchronization portion;
• wherein
• a. said synchronization portion is substantially identical to the synchronization portion of the corresponding first line;
• b. said fourth data segment being substantially identical to said first data segment;
• and
• 3. apparatus for selectively varying the length of said first and second data segments to produce a scramble signal;
• 4. apparatus for transmitting said scrambled signal;
• 5. apparatus for receiving said scrambled signal and for alternately storing selected lines by said scrambled signal in second data storage means having first and second storage locations with each location having sufficient storage capacity to store data representing at least one line of said scrambled signal;
• and
• 6. read apparatus for alternately reading data from said first and second storage locations of said second data storage means to produce a second signal, said second signal being substantially identical to said first signal.

Apparatus for scrambling a signal, said signal including a plurality of first lines with each first line comprising a synchronization portion followed in time by a first data portion, said data portion comprising at least sequentially occurring first and second data segments.

• 1. data storage apparatus having first and second storage locations with each of said location having sufficient storage capacity to store data representing at least one line of said signal;
• 2. storage control apparatus for alternately storing data in and reading said stored data from said first and second storage locations to produce a modified line corresponding to each of said first lines, each modified line consisting of synchronization portion and a second data portion with,
• a. said synchronization portion being substantially identical to the synchronization portion of the corresponding said first line;
• b. said second data portion being substantially identical to said first data portion with said first and second data segments interchanged;
• 3. apparatus for varying the length of said first and second segments in predetermined manner to produce said scrambled signal.