The problem of operationally analyzing spread spectrum frequency-hopping transmissions has been known since the invention of frequency-hopping radios. A frequency-hopping radio transmits a communication using small signal segments of data making up the transmission in accordance to a set of predetermined...http://www.google.co.uk/patents/US7151790?utm_source=gb-gplus-sharePatent US7151790 - Automatic signal extraction and analysis from time-frequency representation
Automatic signal extraction and analysis from time-frequency representation
