DIFF Subgroup
H04K 1/04 by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band
Introduced: September 1968
Full Title
Secret communication > by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band
No child classifications to compare. This is a leaf node in both IPC and CPC.