Roger E J Gerard: Message signal scrambling apparatus. The Marconi Company, Diller Ramik & Wight, November 4, 1980: US04232193 (182 worldwide citation)

In a message signal scrambling apparatus, the signal is divided into elements, each of one time slot duration, and the elements are re-arranged in order so as to produce a signal scrambled in time. Each element is entered and stored in a charge coupled device, from which is extracted as required to ...