Integrated voice and data communications for applications to air traffic control

A possible setup of a data link, compatible with voice transmissions, between aircraft and ground stations is proposed. This method utilizes a hybrid amplitude-phase modulation of the same carrier: the amplitude modulation is used for voice transmission, while the phase modulation is for data transmission. This method is particularly simple to implement and requires only slight modifications to the actual on-board equipment for voice transmission. The interferences between the voice and data signals are evaluated through a computer simulation. Some different phase or frequency modualtions for data transmissions, such as PSK, FSK and MSK, are considered.