SECRET COMMUNICATION

**Definition:** This place covers:

This subclass covers secret line and radiation transmission systems in which the signal is modified at the transmitting station in such a way that the information cannot be intelligibly received without corresponding modification at the receiving station.

The signal can be modified using, for example, frequency scrambling or scrambling by combination with a second signal.

This subclass also covers the jamming of communications and counter-measures against jamming or against surveillance.

**Glossary:** - Secret communication: Secret line and radiation transmission systems, i.e., those in which the signal is modified at the transmitting station in such a way that the information cannot be intelligibly received without corresponding modification at the receiving station. - Jamming of communication: Apparatus, circuits or systems purposefully trying to interfere with the physical transmission and reception of communication. - Frequency scrambling: Transposing or inverting parts of the frequency band or by inverting the whole band - Follower jammer: Jammer adapted to determine and follow the frequency of a jamming target signal that uses frequency hopping techniques - Look-through mode: Operation mode wherein jamming and monitoring of the jamming target alternate - Reactive jammer: Jammer wherein jamming is activated only when a target has been detected - RCIED: Remote Controlled Improvised Explosive Device