(57) A frequency-hopping radio communication system in which a network of stations operate
on the same sequence of frequencies, in synchronism, controlled by pseudo-random generators
which are initially synchronised. Each station has means for modifying its p.r. sequence
dependent only upon the instant in the main line sequence at which the modification
is switched. In order to communicate, one station transmits, on the current main-line
frequency sequence, the address of the desired other station and then signals the
seqence switch. At this instant both transmitting and receiving stations switch to
a modified frequency sequence and are thus isolated from the remaining stations. At
the end of the message a signal from the transmitting to the receiving station causes
both stations to revert to the main line sequence.
|
|
