  By considering generalized synchronizable chaotic systems, the
drive-auxiliary system variables are combined suitably using encryption key
functions to obtain a compound chaotic signal. An appropriate feedback loop is
constructed in the response-auxiliary system to achieve synchronization among
the variables of the drive-auxiliary and response-auxiliary systems. We apply
this approach to transmit analog and digital information signals in which the
quality of the recovered signal is higher and the encoding is more secure.
