method for concealing the information content has been condensed in a limited frequency band

摘要

The scrambling method is designed for signals with a limited band width. Time consecutive sections of the signal voltage, or signals representing it are separately stored, and then read out in parallel at a lower speed during a period equal to their duration. Signals read out from different stores are modulated on different frequency carriers and transmitted by the frequency multiplex method. The processes are reversed at the receiving end and the original sections are read out at the correct speed and sequence. A further scrambling can be achieved by staggering and irregularly changing the order of the stores.